Weldless building structures

ABSTRACT

A building structure including a first building member and a second building member may be connected by a plurality of fasteners, each fastener having a head, a threaded portion having a through hardness of between HRB 70 and HRC 40, a thread-forming portion of at least HRC 50 hardness enabling the fastener to form threads in at least the second steel building member, and a fluted lead portion of at least HRC 50 hardness with a nominal diameter between 70 and 95% of major diameter, such that the fastener is capable of providing a ratio of strip torque to thread-forming torque of at least 3.0 and a ratio of strip torque to drive torque greater than 6.0 when the second steel building member having a thickness of 0.25 inch and the fluted lead portion having at least one diameter within nominal diameter between 80 and 98% of major diameter.

This application claims priority to U.S. Provisional Patent Application61/306,309, filed Feb. 19, 2011.

BACKGROUND AND SUMMARY

This invention relates to building structure components assembled withlittle or no welding required at the construction site.

Steel structural members may be connected to construct various buildingstructures. Various structural members, for example joists, beams,girders, studs, channels, bridging, decking, clips, brackets, and othercomponents may be connected together to form a structure. Typically,steel structural members have been joined by welding the memberstogether, bolting the members together, or a combination of both.

Welded connections have been effectively used in building structures;however, welding steel structural members together during the erectionof a building structure requires a trained welder with welding equipmentat the job site to perform the welding. The difficulty of providingwelded connections increases with difficult and/or remote conditions ofthe construction site, and as the size and height of the structureincreases.

Steel bolts have been used instead of certain welded connections. Atypical prior art connection may include a bolt placed in pre-drilledholes through the components being connected and fastened in place witha nut. To complete a bolted connection, the bolt holes must be alignedsufficiently to pass the bolt through the holes. Then, the bolt must beheld while the nut is turned onto the bolt and tightened. Fastening anut onto the bolt required the installer to have access to both sides ofthe connection. For large structural members, positioning and holdingthe members to align the bolt holes has been a disadvantage. Boltedconnections have been difficult to complete when the pre-drilled holesare not sufficiently aligned, and extra time and effort was required toset the structural members in place for hole alignment and bolting.Additionally, providing pre-drilled holes in each member increased thenumber of unique parts on the job site, increasing the amount timerequired to ensure the proper parts are used in their desired locations.

Another problem in the prior art is securing a plurality of structuralmembers during assembly of certain connections, such as doubleconnections involving two members that share common bolts on either sideof a central piece. Federal regulations by the Occupational Safety andHealth Administration (OSHA) require that for such double connectionsthe first member must be attached before the second member is connected.This typically requires an extra bolt connection for attaching the firstmember positioned so as to not interfere with the placement of thesecond member. The increased complexity of providing pre-drilled holesand complying with OSHA securement requirements has decreased efficiencyin producing and installing the structural members.

Self-drilling and self-threading bolts have been used in certain metalconnections. However, prior self-drilling and self-threading bolts werecase hardened to provide a desired hardness. The prior case hardenedbolts lacked ductility, and the case hardened portion would break whenloaded in certain structural connections causing premature fastenerfailure. Additionally, in connections where the prior self-drillingbolts could be used, additional installation time was required becauseof the difficulty in driving the bolts. Many fastener installations aremade using electric or pneumatic drivers, and for certain applicationsdrivers with rotary impact mechanisms have been used to deliver thetorque needed to install certain fasteners. Without impact mechanisms,drivers typically have been limited to smaller fasteners requiringlimited torque. Impact mechanisms may be used to drive self-threadingfasteners to form threads in the drilled hole in the structural member,and certain prior self-drilling or self-tapping bolts required impactdriving to drive the thread portion of the bolt through the threadedmember. For longer bolts in the past, impact driving was time consumingand inefficient.

Steel bolts and screws have been tried in certain applications to joinsheet metal building members. For example, U.S. Pat. No. 4,982,545discloses a truss that includes web members and chord members fastenedwith screws. However, screws and bolts used in the past for sheet metalconnections have caused assembly problems such as strip-out that haveincreased the time for assembly and increased scrap costs. Strip-outoccurs when the shape of the hole deforms and/or the hole enlarges suchthat the threads of the screw cannot engage the material around the holeenough to tighten the screw or bolt. Additionally, the priorself-drilling bolts experienced high rates of tipping or angledinstallation in sheet metal applications. Strip-out and tipping requiredrework or additional screws to be installed to achieve the desiredconnection strength, increasing time and cost of installation.

Typical prior art self-drilling screw are shown in FIGS. 3A and 3B forconnecting sheet metal components together. The screw has a head, athread portion having a major diameter and a minor diameter, and aself-drilling tip having a notch or flute. In the past, after theself-drilling tip drilled through the material, the threaded portionwould thread into the hole. As the threads typically did not continue tothe head, the driving torque had to be controlled to avoid stripping thescrew in the hole. These screws were relatively easy to strip in a sheetmetal application, causing increased time for assembly and increasedscrap costs. Additionally, certain prior fasteners were tailored toperform in a particular substrate thickness, but when the fasteners wereused in another material thickness, the fasteners could not obtain thesame performance.

What is disclosed is a building structure comprising a first steelbuilding member and a second steel building member connected by aplurality of fasteners, each fastener being steel comprising a headcapable of clamping the first steel building member to the second steelbuilding member with the fastener installed, a threaded portion adjacentthe head, a thread-forming portion adjacent the threaded portion of atleast HRC 50 hardness adapted to form threads into at least the secondsteel building member, and a fluted lead portion adjacent thethread-forming portion of at least HRC 50 hardness with a nominaldiameter in a range from 60% to 95% of major diameter of the threadedportion adapted to form a fastener opening, such that the fastener iscapable of providing a ratio of strip torque to thread-forming torque ofat least 3.0 and a ratio of strip torque to drive torque greater than6.0 over a range of combined thickness of first and second steelbuilding members from 0.036 inch to 0.084 inch.

Alternatively, the fasteners may have a ratio of strip torque tothread-forming torque of at least 3.0 and a ratio of strip torque todrive torque greater than 8.0 over a range of combined thickness offirst and second steel building members from 0.036 inch to 0.084 inch.In yet another alternative, the fasteners may have a ratio of striptorque to thread-forming torque of at least 3.0 and a ratio of striptorque to drive torque greater than 6.0 over a range of combinedthickness of first and second steel building members from 0.036 inch to0.108 inch. For certain applications, the combined thickness of thefirst steel building member and the second steel building member at thefastener may be no more than 0.125 inch in thickness. In any case, thefasteners may be nutable.

The fastener threaded portion adjacent the head may have a throughhardness in a range from HRB 70 and HRC 40. Additionally, the fastenersmay have up to five threads between the threaded portion and thethread-forming portion that are hardened to at least HRC 50 hardness.The threaded portion may have less than 60° thread angle andback-tapered threads. Alternatively, the thread angle may be between 40°and 50°.

In one alternative, threaded portion of the fastener adjacent the headmay have a case hardness of at least HRC 50.

The lead portion of the fluted lead portion of the fasteners may includea milled point, and may have at least HRC 50 hardness. The fluted leadportion may be adapted to form a fastener opening with a diameterbetween 62% and 85% of major diameter of the threaded portion.

The thread-forming portion of the fasteners may have a shape selectedfrom a group consisting of quadlobular and pentalobular. Thethread-forming portion may be from 3 to 7 thread pitch in length.

The fastener threaded portion may extend to adjacent the head of thefastener. Additionally, a sealing member may be positioned between thehead and the threaded portion. The head of the fastener may be undercutand adapted to deform the first steel building member on tightening ofthe fastener. In alternatives in which the head is undercut, a sealingmember may optionally be positioned adjacent the undercut. Alternativelyor additionally, the threaded portion may comprise a major diameterextending to within 1.5 of the thread pitch of the head. Optionally,serrations may be provided in the undercut. In any case, such fastenershave the added advantage of increased back-out resistance and are lesslikely to come loose by vibration.

Also disclosed is a building structure comprising a first steel buildingmember and a second steel building member connected by a plurality offasteners, each fastener being steel comprising a head capable ofclamping the first steel building member to the second steel buildingmember with the fastener installed, a threaded portion adjacent thehead, a thread-forming portion adjacent the threaded portion of at leastHRC 50 hardness adapted to form threads into at least the second steelbuilding member, and a fluted lead portion adjacent the thread-formingportion of at least HRC 50 hardness with a nominal diameter in a rangefrom 60% to 95% of major diameter of the threaded portion adapted toform a fastener opening, such that the fastener is capable of providinga ratio of strip torque to thread-forming torque of at least 4.0 and aratio of strip torque to drive torque greater than 8.0 over a range ofcombined thickness of first and second steel building members from 0.054inch to 0.084 inch.

Alternatively, the fasteners may provide a ratio of strip torque tothread-forming torque of at least 4.0 and a ratio of strip torque todrive torque greater than 10.0 over a range of combined thickness offirst and second steel building members from 0.054 inch to 0.084 inch.Alternatively, the fasteners may have a ratio of strip torque tothread-forming torque of at least 3.5 and a ratio of strip torque todrive torque greater than 6.0 over a range of combined thickness offirst and second steel building members from 0.036 inch to 0.084 inch.In yet another alternative, the ratio of strip torque to thread-formingtorque may be at least 3.5 and a ratio of strip torque to drive torquegreater than 8.0 over a range of combined thickness of first and secondsteel building members from 0.036 inch to 0.084 inch. Alternatively, theratio of strip torque to thread-forming torque may be at least 3.0 and aratio of strip torque to drive torque greater than 4.0 over a range ofcombined thickness of first and second steel building members from 0.036inch to 0.108 inch. For certain applications, the combined thickness ofthe first steel building member and the second steel building member atthe fastener may be no more than 0.125 inch in thickness. In any case,the fasteners may be nutable.

The fastener threaded portion adjacent the head may have a throughhardness in a range from HRB 70 and HRC 40. Additionally, the fastenersmay have up to five threads between the threaded portion and thethread-forming portion that are hardened to at least HRC 50 hardness.The threaded portion may have less than 60° thread angle andback-tapered threads. Alternatively, the thread angle may be between 40°and 50°.

In one alternative, threaded portion of the fastener adjacent the headmay have a case hardness of at least HRC 50.

The lead portion of the fluted lead portion of the fasteners may includea milled point, and may have at least HRC 50 hardness. The fluted leadportion may be adapted to form a fastener opening with a diameterbetween 62% and 85% of major diameter of the threaded portion.

The thread-forming portion of the fasteners may have a shape selectedfrom a group consisting of quadlobular and pentalobular. Thethread-forming portion may be from 3 to 7 thread pitch in length.

The fastener threaded portion may extend to adjacent the head of thefastener. Additionally, a sealing member may be positioned between thehead and the threaded portion. The head of the fastener may be undercutand adapted to deform the first steel building member on tightening ofthe fastener. In alternatives in which the head is undercut, a sealingmember may optionally be positioned adjacent the undercut. Alternativelyor additionally, the threaded portion may comprise a major diameterextending to within 1.5 of the thread pitch of the head. Optionally,serrations may be provided in the undercut. In any case, such fastenershave the added advantage of increased back-out resistance and are lesslikely to come loose by vibration.

In one alternative, the building structure may comprise a first steelbuilding member and a second steel building member connected by aplurality of fasteners, each fastener being steel comprising a headcapable of clamping the first steel building member to the second steelbuilding member with the fastener installed, a threaded portion adjacentthe head having a through hardness in a range from HRB 70 to HRC 40, athread-forming portion adjacent the threaded portion of at least HRC 50hardness adapted to form threads in at least the second steel buildingmember, and a fluted lead portion adjacent the thread-forming portion ofat least HRC 50 hardness with a nominal diameter in a range from 75% to95% of major diameter of the threaded portion adapted to form a fasteneropening, such that the fastener is capable of providing a ratio offailure torque to thread-forming torque of at least 3.0 and a ratio offailure torque to drive torque greater than 6.0 over a range of combinedthickness of first and second steel building members from 0.10 inch to0.32 inch.

Alternatively, the fasteners may be capable of providing a ratio offailure torque to thread-forming torque of at least 3.75. The fastenersmay have a drive torque no more than 50% of a thread-forming torque. Thefasteners may be nutable.

The lead portion of the fluted lead portion of the fasteners may have amilled point, and may have at least HRC 50 hardness.

The fastener thread-forming portion may have a shape selected from agroup consisting of quadlobular, pentalobular and hexalobular. Thethread-forming portion may be from 3 to 7 thread pitch in length.

Additionally, the fasteners may have up to five threads between thethreaded portion and the thread-forming portion that are hardened to atleast HRC 50 hardness. The threaded portion may have less than 60°thread angle and back-tapered threads. Alternatively, the thread anglemay be between 40° and 50°.

Also disclosed is a building structure comprising a first steel buildingmember and a second steel building member connected by a plurality offasteners, each fastener being steel comprising a head capable ofclamping the first steel building member to the second steel buildingmember with the fastener installed, a threaded portion adjacent the headhaving a through hardness in a range from HRB 70 to HRC 40, athread-forming portion adjacent the threaded portion of at least HRC 50hardness adapted to form threads in at least the second steel buildingmember, and a fluted lead portion adjacent the thread-forming portion ofat least HRC 50 hardness with a nominal diameter in a range from 80 to92% of major diameter of the threaded portion adapted to form a fasteneropening, such that the fastener is such that the fastener is capable ofproviding a ratio of failure torque to thread-forming torque of at least3.0 and a ratio of failure torque to drive torque greater than 10 whenthe second steel building member having a thickness of 0.25 inch.

Alternatively, the fasteners may be capable of providing a ratio offailure torque to thread-forming torque of at least 3.0 and a ratio offailure torque to drive torque greater than 10 over a range of secondsteel building member thickness from 0.25 inch to 0.38 inch. Thefasteners may have a drive torque no more than 50% of a thread-formingtorque. The fasteners may be nutable.

The lead portion of the fluted lead portion of the fasteners may have amilled point, and may have at least HRC 50 hardness.

The fastener thread-forming portion may have a shape selected from agroup consisting of quadlobular, pentalobular and hexalobular. Thethread-forming portion may be from 3 to 7 thread pitch in length.

Additionally, the fasteners may have up to five threads between thethreaded portion and the thread-forming portion that are hardened to atleast HRC 50 hardness. The threaded portion may have less than 60°thread angle and back-tapered threads. Alternatively, the thread anglemay be between 40° and 50°.

At least a portion of the threaded portion of the fastener may meet aspecification selected from a group consisting of ASTM A307, ASTM A325,ASTM A354, and ASTM A490 specifications. Alternatively or in addition,at least a portion of the threaded portion of the fastener may meet aspecification selected from a group consisting of SAE J429 Grade 2, SAEJ429 Grade 5, and SAE J429 Grade 8.

Alternatively, a building structure may comprise a first steel buildingmember and a second steel building member connected by a plurality offasteners, each fastener being steel comprising a head capable ofclamping the first steel building member to the second steel buildingmember with the fastener installed, a tapered lead portion having anangle in the range from 30 to 60° of at least HRC 50 hardness adapted tostart into a pilot hole in at least the second steel building member, athread-forming portion of at least HRC 50 hardness adapted to thread thefastener into at least the second steel building member, and a threadedportion having a through hardness of in a range from about HRB 70 to HRC40, such that the fastener and capable of providing a ratio of failuretorque to thread-forming torque of at least 3.0 and a ratio of failuretorque to drive torque greater than 10 when the second steel buildingmember having a thickness of 0.25 inch and the pilot hole having atleast one diameter within nominal diameter from 80 to 98% of majordiameter.

The fasteners may have a drive torque no more than 50% of athread-forming torque. The fasteners may be nutable.

The tapered lead portion of the fasteners may have at least HRC 50induction hardness.

The fastener thread-forming portion may have a shape selected from agroup consisting of quadlobular, pentalobular and hexalobular. Thethread-forming portion may be from 3 to 7 thread pitch in length.

Additionally, the fasteners may have up to five threads between thethreaded portion and the thread-forming portion that are hardened to atleast HRC 50 hardness. The threaded portion may have less than 60°thread angle and back-tapered threads. Alternatively, the thread anglemay be between 40° and 50°.

At least a portion of the threaded portion of the fastener may meet aspecification selected from a group consisting of ASTM A307, ASTM A325,ASTM A354, and ASTM A490 specifications. Alternatively or in addition,at least a portion of the threaded portion of the fastener may meet aspecification selected from a group consisting of SAE J429 Grade 2, SAEJ429 Grade 5, and SAE J429 Grade 8.

Also described is a method of connecting a plurality of members in abuilding connection comprising providing a first building member havinga first mounting surface and a second mounting surface opposite thefirst mounting surface and a first member thickness there between,providing at least one fastener having a thread-forming portion and athreaded portion, positioning a second building member having a firstaperture adjacent the first mounting surface, installing the fastenerthrough the first aperture and forming threads in a fastener openingthrough the first member thickness connecting the second member to thefirst member with the thread-forming portion extending through thesecond mounting surface, positioning a third building member having asecond aperture larger than the major diameter of the threaded portionadjacent the second mounting surface such that the second aperture ispositioned over the threaded portion, and installing a nut over thethreaded portion to connect the third member to the first member.

The step of providing at least one fastener may include providing asteel fastener comprising a head capable of clamping the second buildingmember to the first mounting surface with the fastener installed, athreaded portion adjacent the head having a through hardness in a rangefrom HRB 70 to HRC 40, a thread-forming portion adjacent the threadedportion of at least HRC 50 hardness adapted to form threads in thefastener opening, and a fluted lead portion adjacent the thread-formingportion of at least HRC 50 hardness with a nominal diameter in a rangefrom 80 to 98% of major diameter of the threaded portion adapted to formthe fastener opening, such that the fastener is nutable and capable ofproviding a ratio of failure torque to thread-forming torque of at least3.0 when the first member thickness is 0.25 inch.

Additionally, the method may further include after the step of providinga first member, providing the fastener opening through the first memberthickness, and where the step of providing at least one fastenercomprises providing a steel fastener comprising a head capable ofclamping the second building member to the first mounting surface withthe fastener installed, a tapered lead portion having an angle from 30to 60° of at least HRC 50 hardness adapted to start into the fasteneropening in the first member thickness, a thread-forming portion of atleast HRC 50 hardness adapted to thread the fastener into the fasteneropening, and a threaded portion having a through hardness of in a rangefrom about HRB 70 to HRC 40, such that the fastener is nutable andcapable of providing a ratio of failure torque to thread-forming torqueof at least 3.0 when the first member thickness is 0.25 inch and thefastener opening having at least one diameter within nominal diameter ina range from 80 to 98% of major diameter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial prospective view of a floor joist system of thepresent disclosure;

FIG. 2 is a partial prospective view of an alternative embodiment of thefloor joist system of FIG. 1;

FIGS. 3A and 3B are side views of prior art self-drilling bolts;

FIG. 3C is a side view of a prior self-threading bolt;

FIGS. 4A and 4B are side and end views respectively of a thread-formingfastener of the present disclosure;

FIG. 4C includes alternative thread-forming portions of the fastener ofFIG. 4A;

FIG. 4D illustrates alternative cross-sections through thethread-forming portion shown in FIG. 4C;

FIGS. 5A and 5B are side and end views respectively of a self-drilling,thread-forming fastener of the present disclosure;

FIGS. 5C and 5D are side and end views respectively of an alternativeself-drilling, thread-forming fastener of the present disclosure;

FIG. 5E includes side views of self-drilling, thread-forming stand-offscrews of the present disclosure;

FIG. 6 is a graph of torque over time during installation representingthe thread-forming fastener of FIG. 4A installed in a steel sheet havinga thickness of about 0.25 inch;

FIG. 7 is a graph of torque to over time during installationrepresenting alternative thread-forming fasteners of FIG. 4A installedin a steel sheet having a thickness of about 0.25 inch;

FIG. 8 is a graph of torque to over time during installation for acomparative self-drilling fastener installed in a steel sheet having athickness of about 0.25 inch;

FIG. 9A is a graph of thread-forming torque, failure torque, and failureto thread-forming torque ratios for a ¼ inch major diameter selfdrilling, thread-forming fastener of FIG. 5A and a comparative sampleinstalled in steel sheets of various thicknesses;

FIG. 9B is a graph of thread-forming torque, failure torque, and failureto thread-forming torque ratios for a ⅜ inch major diameter selfdrilling, thread-forming fastener of FIG. 5A and a comparative sampleinstalled in steel sheets of various thicknesses;

FIG. 10 is a graph of torque to over time during installation for theself-drilling, thread-forming fastener of FIG. 5A installed in two steelsheets having a combined thickness of about 0.06 inch;

FIG. 11 is a graph of torque to over time during installation foralternative self-drilling, thread-forming fasteners of FIG. 5A installedin two steel sheets having a combined thickness of about 0.06 inch;

FIG. 12 is a graph of torque to over time during installation for acomparative self-drilling fastener installed in two steel sheets havinga combined thickness of about 0.06 inch;

FIGS. 13A through 13D are graphs of seating torque calculated for ¼ inchself-drilling, thread-forming fasteners and comparative samples forvarious material thicknesses;

FIG. 14 is a graph of torque to over time during installation for theself-drilling, thread-forming fastener of FIG. 5A installed in a steelsheet having a thickness of about 0.187 inch;

FIG. 15 is a graph of torque to over time during installation for acomparative self-drilling fastener installed in a steel sheet having athickness of about 0.187 inch;

FIG. 16 is a flush mounted joist seat;

FIG. 17 is an alternative joist seat;

FIGS. 18A-18C are perspective views of a bolted connection of twobridging members;

FIG. 19 is a side view of a bolted connection of two structural members;

FIG. 20 is a perspective view of a bolted seat connection for a joist ona column flange;

FIG. 21A is a top view of a bolted seat connection on a hollowstructural section;

FIGS. 21B and 21C are top views of prior art bolted seat connections ona hollow structural section;

FIG. 22A is a perspective view of a joist connection on a wide flangegirder;

FIG. 22B is a perspective view of an alternative joist connection on awide flange girder;

FIG. 23 is a side view the joist connection of FIG. 22B;

FIG. 24 is a partial cross sectional view through the joist connectionof FIG. 23;

FIGS. 25A and 25B are perspective views of joist and wide flange girderbrace;

FIG. 26 is a partial prospective cut-away view of the floor joist systemof FIG. 1;

FIG. 27 is a prospective view of joists with diagonal bridging;

FIG. 28A-28C are partial sectional views showing connections of bridgingmembers to joists from FIG. 27;

FIG. 29 is an exploded perspective view from FIG. 27;

FIG. 30 is a perspective detail view from FIG. 27;

FIG. 31 is a perspective view of a plurality of joists and a joist beinglifted by a crane;

FIG. 32 is a perspective view of a chevron bridging configuration;

FIG. 33 is a prospective view of a joists with horizontal bridging andwall terminus connection;

FIG. 34 is a partial side view of a structural knee joint of a metalbuilding system;

FIG. 34A is a partial cross-sectional view of the knee joint of FIG. 26;

FIG. 35 is a partial top view of a girt lap joint;

FIG. 36 is a partial top view of an inset mounted girt lap joint;

FIG. 37 is a partial top view of a flush mounted girt lap joint;

FIG. 38 is a partial top view of a girt corner connection;

FIG. 39 is a partial top view of a flush mounted nested girt connection;

FIG. 40 is a partial side view of a high eave girt connection;

FIG. 41 is a partial perspective view of a purlin lap joint;

FIG. 42A through 42C are partial perspective views of alternative purlinconnections to a roof beam;

FIG. 43 is a partial perspective view of a purlin connection in a roofvalley;

FIG. 44 is a partial end view of a connection of a door jamb to a girt;

FIG. 45 is a partial end view of a connection of a door jamb to a raftermember;

FIG. 46 is a partial side view of an alternative structural knee joint;

FIG. 47 is a partial side view of a rafter member and column connection;

FIG. 48 is a partial side view of a connection of mezzanine beam membersand a column;

FIGS. 49A and 49B is a partial side view of an alternative connection ofmezzanine beam members to a column;

FIG. 49C is a prior art connection of mezzanine beam members to acolumn;

FIG. 50 is yet another alternative connection of connection of mezzaninebeam members to a column;

FIG. 51 is a side view of a connection of rafters to a column;

FIG. 52 is a side view of an alternate connection of a rafter to acolumn;

FIG. 53 is an endwall stub connection to a column and roof beam;

FIG. 54 is a end view of an eave extension;

FIGS. 55A and 55B is a connection of diagonal bracing;

FIG. 55C is a prior art connection of diagonal bracing;

FIG. 56 is a side view of an alternative diagonal bracing;

FIG. 57 is a partial cross-sectional view showing connection of a pipestrut;

FIG. 58 is a partial side view of a wind column and brace strutconnection;

FIGS. 59A and 59B are views of rod and cable braces for use with bracestrut connections such as shown in FIG. 58;

FIG. 60A is a perspective view of a purlin transition connection;

FIG. 60B is a side view of the purlin transition connection of FIG. 52B;

FIG. 61 is a side view of a parapet connection;

FIG. 62 is a side view of a fascia connection;

FIG. 63A is a side view of a crane rail connection;

FIG. 63B is a cross-sectional view through the crane rail of FIG. 55;

FIG. 64 is a partial side view of a concrete wall attachment;

FIG. 65 is a partial cross-sectional view of a lapped connection of twocorrugated metal panels;

FIG. 66 is a partial cross-sectional view of a filler panel of thepresent disclosure;

FIG. 67 is a partial cross-sectional view of a prior art filler panel;

FIG. 68 is a side view of a joist with a utility hanger;

FIG. 69 is a partial cross-sectional view of the utility hanger of FIG.60;

FIG. 70 is an exploded detail view of the utility hanger of FIG. 60;

FIG. 71 is a partial perspective view of a joist with an off-panelsupport brace;

FIG. 72 is a partial perspective view of truss members secured to asupport member;

FIG. 73 is a partial perspective view of an alternative connection oftruss members to a support member;

FIG. 74 is a partial perspective view of truss members secured to asupport member with a blocking member installed;

FIG. 75 is a partial perspective view of jack truss secured to a girdertruss;

FIG. 76 is a partial sectional view of a ridge rafter and rafterconnection;

FIG. 77 is a partial perspective view of roof decking secured to a studwall frame;

FIG. 78 is a partial perspective view of shear wall connection;

FIG. 79 is a partial perspective view showing a hold-down attachment;

FIG. 80 is a partial perspective view of a connection of a header beammember;

FIG. 81 is a partial perspective view of a connection of an alternateheader beam member and exploded view of the header beam member;

FIG. 82 is a partial sectional view of a outer wall and floor trussconnection;

FIG. 83 is a partial side view of a truss member secured to a steel wallstud; and

FIG. 84 is a side and top view of a truss member secured to a girdertruss.

DETAILED DESCRIPTION OF THE DRAWINGS

Turning now to FIGS. 1 and 2, a building structure may include a floorjoist system 100 and at least one load and typically two or more bearingmember 110. The floor joist system 100 may comprise a plurality ofjoists 40 transverse to the load bearing member 110 spaced between loadbearing members 110, and supporting a steel deck 42. The steel deck 42is typically made of side-by-side corrugated member, covered by aconcrete slab 44. The load bearing member 110 may include a girder 46 asshown in FIG. 1. Alternatively, the load bearing member 110 may be aload bearing wall 48 comprising a plurality of studs 50 as shown in FIG.2. The load bearing member may comprise other structural members asdesired to support the floor joist system 100.

Various building members in the building structure may be connectedtogether and secured by a plurality of thread-forming fasteners 52 suchas shown in FIG. 4A, or by a plurality of self-drilling, thread-formingfastener 54 such as shown in FIG. 5A, or by a plurality of case hardenedthread-forming self-drilling fasteners such as shown in FIG. 5C. Forexample, a first steel building member, such as a joist 40, may beconnected to a second steel building member, such as the load bearingmember 110, by a plurality of the thread-forming fasteners 52, or by aplurality of the self-drilling, thread-forming fastener 54.

Each thread-forming fastener 52 is a fastener of steel having a taperedlead portion 62 tapering at an angle in a range from 30° to 60° of atleast Rockwell C-Scale hardness (HRC) 50 induction hardness adapted tostart into a pilot hole 70, which may be pre-drilled, pre-punched orotherwise formed, in at least the second steel building member, such asshown in FIGS. 8 and 9. The thread-forming fastener 52 includes athread-forming portion 66 of at least HRC 50 hardness adapted to threadthe fastener 52 into at least the second building member, and a threadedportion 64 adjacent the thread-forming portion 66. As used in thespecification herein and the appended claims, the word adjacent meanseither adjoining or nearby; as used herein adjacent features may or maynot be contiguous. The thread-forming fastener 52 has a head 63 capableof clamping the first steel building member to the second steel buildingmember with the fastener 52 installed. The threaded portion 64 has amajor diameter 58, i.e. the diameter of the fastener at the tip of thethread, and a minor diameter 59, i.e. the diameter of the fastener atthe root of the thread, as shown in FIG. 4. The fastener 52 has adesired thread pitch 60, i.e. the distance from one thread tip to theadjacent thread tip along the length of the fastener, as shown in FIG.4A.

At least a portion of the threaded portion 64 of the thread-formingfasteners 52 adjacent the head 63 may have a hardness between aboutRockwell B-Scale hardness (HRB) 70 and HRC 40. In one alternative, atleast a portion of the threaded portion 64 has a through hardnessbetween about HRC 25 and HRC 34. In one alternative, at least a portionof the threaded portion 64 has a through hardness between about HRB 70and HRB 100. In one alternative, at least a portion of the threadedportion 64 has a through hardness between about HRC 19 and HRC 30. Inone alternative, at least a portion of the threaded portion 64 has athrough hardness between about HRC 26 and HRC 36. In yet anotheralternative, at least a portion of the threaded portion 64 has a throughhardness between about HRC 33 and HRC 39. The hardness of at least aportion of the threaded portion 64 may be selected to comply with ASTMA307, ASTM A325, ASTM A354, ASTM A490 or other fastener standard.Alternatively or in addition, the hardness of at least a portion of thethreaded portion 64 may be selected to comply with SAE J429 Grade 2, SAEJ429 Grade 5, and SAE J429 Grade 8, or other fastener standard. Adjacentthe threaded portion 64, the thread-forming portion 66 may have ahardness greater than about HRC 50, and may be greater than about HRC54. Up to five threads between the threaded portion 64 and thethread-forming portion 66 may be hardened to at least HRC 50 or at leastHRC 54, and at least a majority of the threaded portion 64 of thethread-forming fasteners 52 is through-hardened such that the fasteneris ductile through the threaded portion. As the thread-forming fastener52 is installed connecting a first steel building member and a secondsteel building member, the fastener 52 may be tightened to clamp thefirst member between the head 63 and the formed threads in the secondbuilding member. As the thread-forming fastener 52 is tightened, aportion of the ductile threaded portion 64 between the head 63 and thethreads engaging the second building member elongates providing aclamping load on the connection according to design requirements. In thepast, thread-forming fasteners had case hardened threads that could notelongate in clamping without risk of fracture or hydrogen embrittlement.The present thread-forming fasteners 52 have sufficient ductility forstructural connections such as slip-critical connections in which thematerials joined are clamped together without slippage by the tensioninduced in the fasteners.

The thread-forming fastener 52 may have a major diameter between about ¼inch, or smaller, and 1½ inch, or larger. In a connection of first andsecond steel building members, the first steel building member may havea clearance hole 72 having a diameter larger than the major diameter ofthe fastener 52. The second steel building member has the pilot hole 70aligned with the clearance hole in the first member, the pilot holebeing smaller than the major diameter of the fastener 52, and typicallylarger than the minor diameter, although for thin metal applications,such as thinner than 14 gage, or less than 16 gage, the pilot hole maybe smaller than the minor diameter. The pre-drilled or pre-punched pilotholes 70 in the second steel building member may be adapted toinstalling thread-forming fasteners 52, the pilot holes 70 having a borediameter between about 70% and 98% of the major diameter 58.Alternatively, the pilot hole bore diameters for installing thethread-forming fasteners 52 may be between about 80% and 98% of themajor diameter 58, and alternatively between about 80% and 95% of themajor diameter. The diameter of the pilot hole may be selected based onthe thickness of the second building member, the major diameter of thefastener, and the desired thread-forming torque. The thread-formingfastener 52 is installed through the clearance hole 72 and rotated intothe pilot hole 70. The thread-forming portion 66 forms threads in thebore of the pilot hole for the threaded portion 64 to engage the secondmember. The thread-forming fastener 52 is tightened to clamp the firstmember between the head 63 and the formed threads in the second member.Alternatively, the first and second members are both provided with pilotholes and the thread-forming portion 66 forms threads in the bore of thepilot holes in both the first and second members for the threadedportion 64 to engage the first and the second member. Optionally, thethread-forming fastener 52 may include an unthreaded shank portion (notshown) between the head 63 and the threaded portion 64 as desired forthe connection. If provided, the length of an unthreaded shank portionand the axial length of the threaded portion 64 may be selectedaccording to the thickness of the first and second building members anddesired length of thread engagement. For example, in certainbearing-type connections with threads excluded from the shear plane, anunthreaded shank portion (not shown) may be desired having a lengthgreater than the thickness of the first building member such that thethreaded portion 64 engages the second building member clamping thefirst building member between the head 63 and the threads engaging thesecond building member. In any case, the threaded engagement with thefirst and/or second building member acts as a nut, and in certainapplications, no nut may required based on design requirements. Examplesof various configurations of installation of thread-forming fasteners 52clearance holes and pilot holes are disclosed in applications describedherein, and each application disclosed is not limited to theconfiguration described.

Shown in the graph of FIG. 6 is the installation torque over time for 5test samples of the self-drilling, thread-forming fastener 54 identifiedas manufacturer's samples 360-80901-60, representative of thethread-forming portion and threaded portion of the thread-formingfastener 52 having a major diameter of ⅜ inch installed into a pilothole at 175 revolutions per minute into a ¼ inch thick plate. As thethread-forming fastener 52 is driven into the pilot hole in the ¼ inchthick plate, a thread-forming torque 74 is the largest torque used torotate the thread-forming portion 66 of the thread-forming fastener 52into the pilot hole 70 forming threads in the pilot hole. After the head63 makes contact with the first building member, further rotationadvances the threaded portion 64 into the threaded fastener opening withincreasing torque as the head clamps the members against the threadsformed in the second member. The operator stops tightening the fastenerat a seating torque 78 as desired lower than the failure torque 80. Thedrive torque 76 is the torque right before the torque rise to seating,as shown in FIG. 6. Continued rotation of the fastener may furtherincrease the torque needed to turn the fastener until the boltedconnection fails at the failure torque 80. The failure mode typically isdetermined by the thickness of the building members and the majordiameter 58 of the fastener. When the building member in which threadsare formed is a thin material such as less than 14 gage, or less than 16gage, the material of the building member may deform or fracture and thefastener strip-out at a strip torque. Failure torque 80 generally refersto strip torque in building members of thinner thickness. For certainmaterial thicknesses, the fastener will fracture at the failure torque80.

The installation torque over time for the thread-forming fastener 52 wasmeasured using self-drilling, thread-forming fasteners 54 installed in apre-drilled pilot hole to negate effects of the fluted lead portion.Five samples having a major diameter of ⅜ inch were installed at 175revolutions per minute into pilot holes in a steel member having athickness of about 0.25 inch and plotted in the graph of FIG. 6. Thethread-forming torque 74 as shown in the graph of FIG. 6 is less thanabout 200 inch-pounds. The drive torque 76, before the torque rises toseating, is less than about 25 inch-pounds. The failure torque 80 isgreater than 600 inch-pounds. For certain samples, the failure torque isgreater than 700 inch-pounds, and one sample greater than about 900inch-pounds. The failure torque 80 shown in FIG. 6 is a strip torque for4 of the 5 samples. The trace identified as “A” in FIG. 6 shows a dropto 0 inch-pounds after reaching the failure torque because fastener Afractured at the failure torque. The ratio of failure torque tothread-forming torque is at least 3.0, and the ratio of failure torqueto drive torque may be greater than 6.0 when the steel member has athickness of 0.25 inch (about 6.35 millimeter) and the pilot hole havingat least one diameter within nominal diameter between 85 and 90% ofmajor diameter. Alternatively, the ratio of failure torque to drivetorque may be greater than 10, and may be greater than 20. The ratio offailure torque to drive torque may be as high as 50 to 100, or more,when the second building member having a thickness of 0.25 inch and thepilot hole having at least one diameter within nominal diameter between80 and 98% of major diameter.

Further testing of ⅜ inch major diameter thread-forming fasteners 52 isshown in FIG. 7. As with the experiment shown in FIG. 6, theinstallation torque over time for the thread-forming fastener 52 wasmeasured using ten samples of self-drilling, thread-forming fasteners54, identified as manufacturer's samples 360-80952-60 having a majordiameter of ⅜ inch, installed in pre-drilled pilot holes to negateeffects of the fluted lead portion. The samples were installed at 175revolutions per minute into 0.302 inch diameter pilot holes in a steelmember having a thickness of about 0.25 inch and plotted in the graph ofFIG. 7. In this test sample, the average thread-forming torque 74 of thesamples was 316.6 inch-pounds. As shown in the graph of FIG. 7, thethread-forming torque is less than about 350 inch-pounds. The drivetorque 76, before the torque rises to seating, is less than about 100inch-pounds. The failure torque 80 is greater than 600 inch-pounds. Forcertain samples, the failure torque is greater than 700 inch-pounds, andone sample greater than 800 inch-pounds.

FIG. 8 shows installation torque over time for comparative samples ofprior ⅜ inch fasteners. The comparative fasteners lacked the presentthread-forming portion, instead utilizing prior technology. The graph ofFIG. 8 shows the higher thread-forming torque required to drive theprior fasteners. The average thread-forming torque of the ten sampleswas 373.4 inch-pounds. Additionally, the drive torque is significantlyhigher than the present fasteners as shown in FIG. 7. The drive torquefor the comparative fastener samples is greater than 200 inch-pounds,and for most samples is greater than 250 inch-pounds. The ratio offailure torque to drive torque for the comparative fasteners is lessthan 4. Additionally, as shown by the graph of FIG. 8 and TABLE 1, thevariation in performance among the comparative samples was much higherthan the present fastener as shown by the standard deviation of thedata.

TABLE 1 Mean Standard Mean Standard Thread-Forming Deviation FailureDeviation Torque Thread-Forming Torque Failure (in-lbs) Torque (in-lbs)Torque Present 316.6 9.8 708.1 53.4 Invention, FIG. 7 Comparative 373.437.5 685.1 136.1 Invention, FIG. 8

The consistent performance of the present fastener provides betterpredictability. In certain applications, additional prior fasteners wereadded to accommodate the inconsistent performance of the priorfasteners. In these applications, the improved performance and decreasedvariation of the present fasteners 52 may allow a fewer number offasteners to be used to provide the desired design requirement at anincreased efficiency.

The thread-forming portion 66 of thread-forming fastener 52 may have abilobular, trilobular, quadlobular, pentalobular, hexalobular or othercross-sectional shape. Of these the pentalobular shape has been found todate to give the best performance in thread forming. In any event, theselobar shapes of the thread-forming portion of the fastener control thethread-forming torque and drive torque to facilitate installation of thefastener, reduce failures in installation, and improve the load carryingcapacity of the assembled building members. The thread-forming portionincludes a plurality of relief recesses 57 spaced around thethread-forming portion 66 to segment the thread-forming portion 66 intoa desired number of lobes 77 forming the bilobular, trilobular,quadlobular, pentalobular, hexalobular or other cross-sectional shape.For example, five relief recesses 57 may be spaced as desired around thethread-forming portion 66 to segment the thread-forming portion 66 intofive lobes 77 forming the pentalobular cross-section shown in FIG. 4D,and four relief recesses 145 may be spaced as desired around thethread-forming portion 143 to segment the thread-forming portion 143into four lobes 139 forming the quadlobular cross-section shown in FIG.4D. As shown in FIG. 4C, the relief recesses 57 may be longitudinalrecesses provided along the axial direction of the fastener. In onealternative, the width of the relief recesses 57 may be wider toward thefluted lead portion forming the triangular shape as shown in FIG. 4C.

In some embodiments, the thread-forming portion of the fastener includesa series of lobes 77 with relief recesses 57 between about therotational axis such as shown in FIG. 4D. Each lobe 77 has a leadingportion and a tailing portion, the leading portion and first adjacentrecess may be at a first angle, shown as θ in FIG. 4D, in a range from50° to 100° from a plane tangent to the lobe adjacent the leadingportion, and the tailing portion and second adjacent recess may be at asecond angle, shown as γ in FIG. 4D, in a range from 25° to 50° from aplane tangent to the lobe adjacent the tailing portion. As shown in FIG.4D, the first angle may be greater than the second angle. Alternatively,the second angle between the tailing portion and second adjacent recessmay be in a range from 50° to 100° from a plane tangent to the lobeadjacent the tailing portion. In this alternative, the first angle andthe second angle may be approximately the same. The recess may includearcuate surfaces and/or flat surfaces forming the intersection betweenthe recess and the lobe forming the first and second angles.

The relief recesses 57 may extend into the threads of the fastener toabout the minor diameter 59. Alternatively, the relief recesses 57 mayextend into the shank of the fastener deeper than the minor diameter 59,such as to a depth between about 80% and 99% of the minor diameter. Inyet another alternatively, the relief recesses 57 may extend into thethreads of the fastener to a depth between the major diameter 58 and theminor diameter 59, such as to a depth between about 101% and 120% of theminor diameter. Each relief recess 57 may be about one thread pitch inwidth. Alternatively, the relief recesses 57 may be between about 0.8and 4 thread pitches wide. In one alternative, the width of the reliefrecesses 57 may be between about 30% and 70% of the formula (π×majordiameter/number of lobes) as desired to provide desired separationbetween the lobes 77. In yet another alternative, the width of therelief recesses 57 may be between about 40% and 60% of the formula(π×major diameter/number of lobes). For example, in one applicationhaving 4 lobes (quadralobular), the width of the relief recesses may beapproximately 60% of the formula (π×major diameter/number of lobes). Inanother example, in one application having 2 lobes (bilobular), thewidth of the relief recesses may be approximately 50% of the formula(π×major diameter/number of lobes). The relief recesses 57 of thethread-forming portion 66 may be between about 3 to 7 thread pitches 60in axial length. Alternatively, the relief recesses 57 of thethread-forming portion 66 may be between 2 and 5 thread pitches 60 inaxial length. Depending upon the size of the fastener, thethread-forming portion 66 may be between about 0.06 and 0.5 inches inlength, and may have a thread-forming torque of no more than about ⅓ ofthe failure torque 80. In any event, the thread-forming torque is lessthan the torsional strength of the fastener to avoid failure. In onealternative, the thread-forming torque is less than 80% of the torsionalstrength of the fastener.

The threaded portion 64 of the thread-forming fastener 52 is adapted toinstall at a drive torque 76 at least 50% less than the thread-formingtorque 74, i.e. no more than 50% of the thread-forming torque. In onealternative, the drive torque is less than 30% of the thread-formingtorque. Alternatively, the drive torque 76 is between about 5% and 60%of the thread-forming torque 74. To reduce driving torque, the threadedportion 64 may include back-tapered threads, and may have a thread angleless than 60°, represented as a in FIG. 4A. Alternatively, the threadangle may be less than 50°. In yet another alternative, such threadangle may be between 45 and 50°. Reducing the thread angle also reducesthe thread pitch 60 and reduces the minor diameter 59. Back-taperedthreads as used herein means that the major diameter 58 of the threadedportion 64 has a back-taper such that the major diameter 58 is largeradjacent the thread-forming portion 66 than the major diameter 58adjacent the head 63. In certain embodiments, the back-taper of themajor diameter may be between about 0.0005 and 0.005 inch per inch ofaxial length. Alternatively, the back-taper may be between about 0.001and 0.003 inch per inch of length.

The threaded portion 64 of fastener 52 may provide a failure torque 80of at least 600 inch-pounds measured using a fastener 52 having a majordiameter of ½ inch threaded into a pilot hole having at least onediameter within nominal diameter between about 80% and 98% of the majordiameter 58 and the threaded member having a material thickness of about0.25 inch (about 6.35 millimeter). For material thicknesses greater than0.25 inch, the threaded portion may have a seating torque of at least400 inch-pounds. Alternatively, the threaded portion has seating torqueof at least 600 inch-pounds, and may be at least 800 inch-poundsmeasured using a ½ inch fastener threaded into a pilot hole having atleast one diameter within nominal diameter between about 80% and 98% ofthe major diameter 58 and the threaded member having a materialthickness of about 0.25 inch (about 6.35 millimeter).

The thread-forming fastener 52 may be used in connections such as shownin FIGS. 16 and 17, where the first steel building member, such as thejoist 40, includes a clearance hole 72 having a bore diameter largerthan the major diameter 58 of the fastener. The second steel buildingmember, such as the girder 46, includes the pilot hole 70. The pilothole 70 may have a bore diameter between about 70% and 95% of the majordiameter 58. Alternatively, the pilot hole 70 may have a bore diameterbetween about 80% and 98% of the major diameter, and alternatively,between about 80% and 95% of the major diameter 58. The thread-formingfastener 52 may be positioned through the clearance hole 72 in the firstmember and driven into the pilot hole 70 of the second member. Thethread-forming portion 66 forms threads in the bore of the pilot holeenabling the threaded portion 64 to be threaded into the second member,clamping the first member between the head 63 and the threads formed inthe second member. The thread-forming fastener 52 may have a majordiameter between about ¼ inch and 1 inch, or greater as desired for thesize and load requirements for the connection in the assembly. At leasta portion of the threaded portion 64 of the thread-forming fastener 52as shown in FIGS. 16 and 17 may comply with ASTM A307, A354, A325, A490,or other fastener standard as required.

Alternatively, for certain connections, both the first member and thesecond member may include the pilot hole 70, wherein the thread-formingportion 66 forms threads in both the first and second members.

The self-drilling, thread-forming fastener 54, as shown in FIGS. 5Athrough 5D, are fasteners of steel comprising the head 63 capable ofclamping the first steel building member to the second steel buildingmember with the fastener installed. The self-drilling, thread-formingfastener 54 includes the threaded portion 64 adjacent the head 63, andthe thread-forming portion 66 as discussed above adjacent the threadedportion 64 of at least HRC 50 hardness adapted to enable the fastenerform threads into at least the second building member. Theself-drilling, thread-forming fastener 54 has a fluted lead portion 68at the tip of the fastener 54 and adjacent the thread-forming portion 66of at least HRC 50 hardness with a nominal diameter between about 70 and95% of the major diameter 58 of the threaded portion 64 adapted to formthe fastener opening, or pilot hole 70, and typically larger than theminor diameter, although for thin metal applications, such as thinnerthan 14 gage, or less than 16 gage, the nominal diameter of the flutedlead portion 68 may be smaller than the minor diameter. Alternatively,the fluted lead portion 68 has a nominal diameter between about 80% and95% of the major diameter 58.

The fluted lead portion 68 may have a swaged or pinched point, a milledpoint, or a combination of both. The milled point alone, or incombination with preformed swedged or pinched point, is generallydesired to ensure effectiveness of the fluted lead portion in drillingthrough the building members. The length of the fluted lead portion 68may be longer than the thickness of the building member through whichthe fluted lead portion drills. It may be useful to provide the flutedlead portion 68 having an axial length between about 1.1 and 2.0 timesthe thickness of the drilled building member. The fluted lead portion 68may be a Type 1, Type 2, Type 3, Type 4, Type 5, or a variation thereof.

At least a portion of the threaded portion 64 of the self-drilling,thread-forming fastener 54 may have a hardness between about HRB 70 andHRC 40 through hardness. In one alternative, at least a portion of thethreaded portion 64 has a hardness between about HRC 25 and HRC 34. Inone alternative, at least a portion of the threaded portion 64 has athrough hardness between about HRB 70 and HRB 100. In one alternative,at least a portion of the threaded portion 64 has a through hardnessbetween about HRC 19 and HRC 30. In one alternative, at least a portionof the threaded portion 64 has a through hardness between about HRC 26and HRC 36. In yet another alternative, at least a portion of thethreaded portion 64 has a through hardness between about HRC 33 and HRC39. As discussed above, the hardness of the threaded portion 64 may beselected to comply with ASTM A307, ASTM A325, ASTM A354, ASTM A490 orother fastener standard. Alternatively or in addition, the hardness ofthe threaded portion 64 may be selected to comply with SAE J429 Grade 2,SAE J429 Grade 5, and SAE J429 Grade 8, or other fastener standard.

In yet another alternative, the self-drilling, thread-forming fastenermay be case hardened to at least HRC 50. For certain applications, theself-drilling, thread-forming fastener may be a case hardened fastener.In the figures, such as FIGS. 1 and 2, in which under certainapplications may utilize a case hardened self-drilling, thread-formingfastener, the fastener will be referenced as a case hardenedself-drilling, thread-forming fastener 56. The case hardenedself-drilling, thread-forming fastener 56 may have a major diameter 58of between about 0.18 and 0.26 inch.

Adjacent the thread-forming portion 66, a portion of the threadedportion 64 may have a hardness greater than about HRC 50, and may begreater than about HRC 54. Up to five threads between the threadedportion and the thread-forming portion 66 may be hardened to at leastHRC 50 or at least HRC 54. The threaded portion 64 of the self-drilling,thread-forming fastener 54 may be through-hardened such that thefastener is ductile through the threaded portion. As discussed above, asthe self-drilling, thread-forming fastener 54 is installed connecting afirst steel building member and a second steel building member, thefastener 52 may be tightened to clamp the first member between the head63 and the formed threads in the second building member. As thethread-forming fastener 52 is tightened, a portion of the threadedportion 64 between the head 63 and the threads engaging the secondbuilding member elongate providing a clamping load on the connectionaccording to design requirements. The present thread-forming fasteners52 have sufficient ductility for structural connections such asslip-critical connections.

The self-drilling, thread-forming fastener 54 typically has a majordiameter between about 0.12 inch and about ½ inch. In certain instances,the size of the fastener 54 may be limited by the ability of the flutedlead portion 68 to function in drilling at larger sizes. In a connectionbetween a first and a second building member, the first building membermay have a clearance hole 72 having a diameter larger than the majordiameter of the fastener 54. The self-drilling, thread-forming fastener54 is installed through the clearance hole and rotated into the secondmember. The fluted lead portion 68 drills an opening through the secondmember, and the thread-forming portion 66 forms threads in the bore ofthe drilled fastener opening for the threaded portion 64 to engage thesecond building member. The self-drilling, thread-forming fastener 54 istightened to clamp the first member between the head 63 and the threadsformed in the second member. The threaded second member acts as a nut,and in certain applications, no nut may be required based on designrequirements. Alternatively, the self-drilling, thread-forming fastener54 may be installed in a pilot hole, and the thread-forming portion 66forms threads in the bore of the pilot hole for the threaded portion 64to engage the second building member. In yet another alternative,neither clearance hole or pilot hole is provided and the fluted leadportion 68 drills through both the first and second member, and thethread-forming portion 66 forms threads in the bore of the drilledfastener opening for the threaded portion 64 to engage with the formedthreads in both the first and second members. Optionally, theself-drilling, thread-forming fastener 54 may include an unthreadedshank portion (not shown) between the head 63 and the threaded portion64 as desired for the connection. If provided, the length of anunthreaded shank portion and the axial length of the threaded portion 64may be selected according to the thickness of the first and secondbuilding members and desired length of thread engagement. For example,in certain bearing-type connections with threads excluded from the shearplane, an unthreaded shank portion (not shown) may be desired having alength greater than the thickness of the first building member such thatthe threaded portion 64 engages the second building member clamping thefirst building member between the head 63 and the threads engaging thesecond building member. In any case, the threaded engagement with thefirst and/or second building member acts as a nut, and for certainapplications, no nut may be required based on design requirements.Examples of various configurations of installation of self-drilling,thread-forming fastener 54 with and without clearance holes and/or pilotholes are disclosed in applications described herein, and eachapplication disclosed is not limited to the configuration described.

The present self-drilling, thread-forming fastener 54, 56 provides aratio of strip torque to thread-forming torque of at least 3.0 and aratio of strip torque to drive torque greater than 6.0 over a range ofcombined thickness of first and second steel building members from 0.036inch to 0.084 inch. As shown in FIG. 9A, samples of a ¼ inch majordiameter self-drilling, thread-forming fastener 54 of the presentinvention identified as manufacturer's samples ETC045 were installedinto materials of different thicknesses and compared to prior ¼ inchmajor diameter fasteners. For steel sheet samples between 26 gage and 16gage, the fasteners were installed into two sheets together.Additionally, the fasteners were installed into one steel sheetthickness for materials between about 0.109 and 0.25 inch thickness. Tensamples were used for each tested thickness. TABLE 2 shows typical gagethickness for steel sheet (source: Steel Deck Institute).

TABLE 2 ONE SHEET TWO SHEET GAGE THICKNESS THICKNESS 16 .0598 0.120 18.0474 0.096 20 .0358 0.072 22 .0295 0.060 24 .0238 0.048 26 .0179 0.036

FIG. 9A and TABLE 3 show the ratio of strip torque to thread-formingtorque for the tested fasteners. The ¼ inch self-drilling,thread-forming fastener 54 provided a ratio of strip torque tothread-forming torque of at least 3.0 for all thicknesses tested up toand including 0.143 inch thick sheet. Alternatively, the ¼ inchself-drilling, thread-forming fastener 54 provided a ratio of striptorque to thread-forming torque of at least 3.5 for all thicknessestested up to and including 0.143 inch thick sheet. TABLE 4 provides thestrip torque and thread-forming torque for the ¼ inch samples tested.

TABLE 3 ¼ inch Present ¼ inch Invention Comparative Sample Strip Torqueto Strip Torque to Thread-forming Thread-forming Torque Ratio TorqueRatio 26/26 gage 4.01 4.00 24/24 gage 3.73 3.42 22/22 gage 3.56 2.9620/20 gage 4.19 1.95 18/18 gage 4.23 2.27 16/16 gage 4.67 2.43 0.1094.18 2.78 0.113 4.67 2.95 0.123 5.00 2.59 0.133 5.27 2.84 0.143 4.292.84 0.155 2.96 2.94 0.170 2.46 2.26 0.187 2.19 2.23 0.205 2.39 2.180.250 1.62 2.09

TABLE 4 ¼ inch ¼ inch Present Comparative Invention ¼ inch Sample ¼ inchThread- Present Thread- Comparative forming Invention forming SampleTorque Strip Torque Torque Strip Torque (in-lb) (in-lb) (in-lb) (in-lb)26/26 gage 9.73 38.98 3.18 12.73 24/24 gage 14.84 55.37 7.43 25.43 22/22gage 18.01 64.17 10.97 32.43 20/20 gage 13.13 55.06 11.38 22.16 18/18gage 19.69 83.24 18.27 41.55 16/16 gage 26.61 124.25 24.37 59.22 0.10951.14 213.89 36.8 102.37 0.113 55.80 260.42 35.16 103.7 0.123 56.01280.28 41.73 107.98 0.133 57.53 303.09 43.34 123.17 0.143 66.68 285.8745.79 130.26 0.155 94.43 279.12 46.99 138.33 0.170 116.35 286.48 70.25158.82 0.187 114.43 250.67 74.78 167.03 0.205 115.50 275.52 84.04 182.910.250 131.23 212.22 108.13 225.76

The ratio of strip torque to thread-forming torque is at least 3.0 and aratio of strip torque to drive torque greater than 6.0 over a range ofcombined thickness of first and second steel building members from 0.036inch to 0.084 inch. Alternatively, the present self-drilling,thread-forming fasteners 54, 56 may have a ratio of strip torque tothread-forming torque of at least 3.0 and a ratio of strip torque todrive torque greater than 8.0 over a range of combined thickness offirst and second steel building members from 0.036 inch to 0.084 inch.Alternatively, the fasteners may have a ratio of strip torque tothread-forming torque of at least 3.5 and a ratio of strip torque todrive torque greater than 6.0 over a range of combined thickness offirst and second steel building members from 0.036 inch to 0.084 inch.In yet another alternative, the ratio of strip torque to thread-formingtorque may be at least 3.5 and a ratio of strip torque to drive torquegreater than 8.0 over a range of combined thickness of first and secondsteel building members from 0.036 inch to 0.084 inch. In yet anotheralternative, the ratio of strip torque to thread-forming torque may beat least 3.0 and a ratio of strip torque to drive torque greater than4.0 over a range of combined thickness of first and second steelbuilding members from 0.036 inch to 0.108 inch. In another alternative,the fasteners may have a ratio of strip torque to thread-forming torqueof at least 3.0 and a ratio of strip torque to drive torque greater than6.0 over a range of combined thickness of first and second steelbuilding members from 0.036 inch to 0.108 inch. Alternatively, thepresent self-drilling, thread-forming fasteners 54, 56 may have a ratioof strip torque to thread-forming torque of at least 4.0 and a ratio ofstrip torque to drive torque greater than 8.0 over a range of combinedthickness of first and second steel building members from 0.054 inch to0.084 inch. Alternatively, the fasteners may provide a ratio of striptorque to thread-forming torque of at least 4.0 and a ratio of striptorque to drive torque greater than 10.0 over a range of combinedthickness of first and second steel building members from 0.054 inch to0.084 inch.

For certain applications, the self-drilling, thread-forming fasteners54, 56 are capable of providing a ratio of failure torque tothread-forming torque of at least 3.0 and a ratio of failure torque todrive torque greater than 6.0 over a range of combined thickness offirst and second steel building members from 0.10 inch to 0.32 inch. Asshown in FIG. 9B, samples of a ⅜ inch major diameter self-drilling,thread-forming fastener 54 of the present invention identified asmanufacturer's samples 360-80952-60 were installed into a 0.302 diameterpilot hole in materials of different thicknesses and compared to prior ⅜inch major diameter fasteners. The fastener samples were installed intosingle steel sheet thicknesses between about 0.109 and 0.25 inchthickness. Ten samples were used for each tested thickness. TABLE 5shows the ratio of strip torque to thread-forming torque for the testedfasteners. The ⅜ inch self-drilling, thread-forming fastener 54 provideda ratio of strip torque to thread-forming torque of at least 3.0 for allthicknesses tested up to and including 0.187 inch thick sheet. TABLE 6shows the failure torque and the thread-forming torque for the ⅜ inchsamples tested.

TABLE 5 ⅜ inch Present ⅜ inch Invention Comparative Sample Strip Torqueto Strip Torque to Thread-forming Thread-forming Torque Ratio TorqueRatio 0.109 4.54 3.15 0.113 4.34 2.83 0.123 4.32 3.00 0.133 4.17 3.230.143 4.07 3.04 0.155 3.95 2.92 0.170 3.75 2.53 0.187 3.00 2.35 0.2052.68 2.08 0.250 2.24 1.83

TABLE 6 ⅜ inch Present ⅜ inch Invention ⅜ inch Comparative ⅜ inchThread- Present Sample Comparative forming Invention Thread- SampleTorque Strip Torque forming Strip Torque (in-lb) (in-lb) Torque (in-lb)(in-lb) 0.109 121.83 552.62 165.35 520.63 0.113 128.16 556.18 188.02531.63 0.123 136.25 576.89 182.13 545.9 0.133 149.72 625 188.02 608.060.143 176.16 716.7 192 583.56 0.155 186.66 737.11 236.14 690.14 0.170214.49 804.78 286.1 724.11 0.187 223.23 668.83 266.83 673.98 0.205266.46 713.15 342.96 712.69 0.250 316.59 708.05 373.44 685.13

As shown in FIG. 9B and TABLE 4, the ratio of failure torque tothread-forming torque of at least 3.0 for samples tested in materialthicknesses from 0.109 through 0.187. It is contemplated that fastenerswith the present thread-forming portion can obtain a ratio of failuretorque to thread-forming torque of at least 3.0 up to thicknesses of0.32.

As shown in the graph of FIG. 10, the self-drilling, thread-formingfastener 54 has a drilling torque to rotate the fluted lead portion 68into the first and second building members forming the fastener opening.Additionally, the drive torque 76 is at least 50% less than thethread-forming torque 74. As discussed above, the drive torque 76 may bebetween about 5% and 60% of the thread-forming torque 74. Theself-drilling, thread-forming fasteners 54 have the added advantage ofincreased back-out resistance and are less likely to come loose byvibration.

The installation torque over time for the self-drilling, thread-formingfastener 54 was measured and shown in FIG. 10. Five samples identifiedas manufacturer's samples ETC040 having a major diameter of ¼ inch wereinstalled at 175 revolutions per minute into pilot holes correspondingto the fluted lead portion 68 into first and second steel members havinga combined thickness of about 0.06 inch. The thread-forming torque 74 asshown in the graph of FIG. 10 is less than about 20 inch-pounds.Alternatively, the thread-forming torque 74 may be less than about 15inch-pounds. The drive torque 76, before the torque rises to seating, isless than about 6 inch-pounds. The failure torque 80 is greater than 40inch-pounds. For certain samples, the failure torque is greater than 50inch-pounds, and one sample greater than about 60 inch-pounds. Thefailure torque 80 shown in FIG. 10 is a strip torque. The ratio of striptorque to thread-forming torque may be at least 3.0 and the ratio ofstrip torque to drive torque is greater than 6.0 when the first andsecond steel members have a combined thickness of 0.06 inch (about 1.5millimeter) and the nominal diameter of the fluted lead portion 68 isbetween 85 and 90% of major diameter. Alternatively, the ratio of striptorque to thread-forming torque may be at least 3.0 and the ratio ofstrip torque to drive torque is greater than 6.0 when the first andsecond steel members have a combined thickness of 0.06 inch (about 1.5millimeter) and the nominal diameter of the fluted lead portion 68 isbetween 70 and 95% of major diameter. The ratio of strip torque to drivetorque may be greater than 10.

Further testing of ¼ inch major diameter self-drilling, thread-formingfasteners 54 is shown in FIG. 11. As with the experiment shown in FIG.10, the installation torque over time for the self-drilling,thread-forming fastener 54 was measured using ten samples identified asmanufacturer's samples ETC045 having a major diameter of ¼ inchinstalled at 175 revolutions per minute into two 22 gage steel membershaving a combined thickness of about 0.06 inch and plotted in the graphof FIG. 11. In this test sample, the average thread-forming torque 74 ofthe samples was 18 inch-pounds. As shown in the graph of FIG. 11, thethread-forming torque is less than about 20 inch-pounds. The drivetorque 76, before the torque rises to seating, is less than about 10inch-pounds. The failure torque 80 is greater than 60 inch-pounds. Forcertain samples, the failure torque is greater than 65 inch-pounds, andone sample greater than 70 inch-pounds. The average failure torque forthe tested samples of the present ¼ fastener was 64.2 inch-pounds.

FIG. 12 shows installation torque over time for comparative samples ofprior ¼ inch fasteners. The comparative fasteners lacked the presentthread-forming portion, instead utilizing prior technology. The graph ofFIG. 12 shows the significantly lower failure torque of the ten samples.The average failure torque for the tested comparative ¼ inch samples was32.4 inch-pounds.

The present self-drilling, thread-forming fastener 54, 56 provides alarger seating torque window than prior fasteners in certainapplications. The seating torque window is one measure for a range ofseating torques in which the fastener may be installed providing adesired clamping and inhibiting stripping of the fastener or otherfastener failure. FIGS. 13A through 13D show seating torque windows forpresent and comparative test samples installed in two thicknesses of 24gage material (FIG. 13A), two thicknesses of 22 gage material (FIG.13B), two thicknesses of 20 gage material (FIG. 13C), and twothicknesses of 22 gage material (FIG. 13D) as examples of improvementsin seating torque. The seating torque window is calculated using thetest data for strip torque minus three standard deviations of the striptorque data for the upper limit, and the thread-forming torque minusthree standard deviations of the thread-forming torque for the lowerlimit. In the test shown in FIG. 13C, the competitive samples varied sogreatly in failure torque that three standard deviations from the striptorque was lower than the thread-forming torque, shown by a negativetorque window in the table in FIG. 13C. The improved consistency andperformance of the present fasteners provides a greater seating torquewindow for certain applications. The larger seating torque windowprovides a larger seating target for various operators and variousfastener drivers to achieve.

Test results for samples of ⅜ inch major diameter self-drilling,thread-forming fasteners 54 is shown in FIG. 14. The installation torqueover time for the self-drilling, thread-forming fastener 54 was measuredusing ten samples identified as manufacturer's samples 360-80952-60having a major diameter of ⅜ inch installed at 175 revolutions perminute into a single sheet of 0.187 inch thick material and plotted inthe graph of FIG. 14. In this test sample, the average thread-formingtorque 74 of the samples was 223.2 inch-pounds. As shown in the graph ofFIG. 14, the thread-forming torque is less than about 250 inch-pounds.The drive torque 76, before the torque rises to seating, is less thanabout 50 inch-pounds. The failure torque 80 is greater than 600inch-pounds. For certain samples, the failure torque is greater than 650inch-pounds, and several samples were greater than 700 inch-pounds. Theaverage failure torque for the tested samples of the present ⅜ fastenerwas 668.8 inch-pounds.

FIG. 15 shows installation torque over time for comparative samples ofthe prior ⅜ inch fasteners in 0.187 thick material. The graph of FIG. 15shows higher thread-forming torque required to drive the priorfasteners. The average thread-forming torque of the ten samples was286.8 inch-pounds. Additionally, the drive torque is significantlyhigher than the present fasteners as shown in FIG. 14. The drive torquefor the comparative fastener samples is greater than 125 inch-pounds,and for most samples is greater than 150 inch-pounds. The ratio offailure torque to drive torque for the comparative fasteners is lessthan about 5.

To increase the strip torque when the threaded building member is a thinmaterial such as less than 14 gage, or less than 16 gage, the threadedportion 64 may extend to the head 63 such that the major diameter 58 ofthe threaded portion 64 is extending to within 1.5 of the thread pitchof the head 63, as indicated in the detail of FIG. 5A by reference 65.Alternatively, the major diameter extends to within 1.2 thread pitchesof the head 63. In yet another alternative, the major diameter 58extends to within about one thread pitch of the head. Optionally, thehead 63 of the fastener may be undercut such as shown in the detail ofFIG. 5C approximately adjacent where the threaded portion joins the headand adapted to deform the first steel building member on tightening ofthe fastener. Alternatively, the fastener may be undercut and adapted todeform the first and second steel building member on tightening of thefastener. The undercut may include a radius 67 at least about 0.02 inchradius, and may be at least about 0.03 inch radius adjacent where thethreaded portion joins the head. Alternatively, or in addition, aserrated surface may be provided on the underside of the head 63 toengage the surface of the first steel building member. The serratedsurface may comprise serrations, projections, nibs, or otherdeformations or protrusions as desired positioned on the underside ofthe head 63, and may be positioned in the undercut, if provided.

In one alternative, the head is undercut adjacent where the threadedportion joins the head and the major diameter of the threaded portionextends to within 1.5 of the thread pitch of the head. The closeproximity of the threads to the underside of the head further assiststhe deformation of at least the first steel building member into theundercut on tightening of the fastener. We have found that thedeformation of at least the first building member into the undercutimproves the connection strength by increasing the strip torque andinhibiting failure modes caused by tipping of the fastener under sheetsheer when the threaded building member is a thin material such as lessthan 14 gage, or less than 16 gage. In certain applications, theimproved performance the present fasteners 54,56 may allow a fewernumber of fasteners to be used to provide the desired design requirementat an increased efficiency.

The threaded portion 64 of fastener 54 may provide a seating torque ofat least 80 inch-pounds measured using a fastener 54 having a majordiameter of about ¼ inch with the fluted lead portion 68 having at leastone diameter within nominal diameter between about 80% and 95% of themajor diameter 58 and installed in a first and second building memberhaving a combined material thickness of at least 0.125 inch (about 3.2millimeter). Alternatively, the threaded portion has seating torque ofat least 100 inch-pounds, and may be at least 120 inch-pounds measuredusing a ¼ inch fastener with the fluted lead portion 68 having at leastone diameter within nominal diameter between about 80% and 95% of themajor diameter 58 and installed in a first and second building memberhaving a combined material thickness of at least 0.125 inch (about 3.2millimeter).

For larger diameter self-drilling, thread-forming fasteners 54 such ashaving a major diameter 58 of ⅜ inch, the threaded portion 64 offastener 52 may provide a failure torque 80 of at least 600 inch-poundsmeasured using a fastener 54 having a major diameter of ⅜ inch and afluted lead portion 68 having a nominal diameter between about 80% and98% of the major diameter 58 and the threaded member having a materialthickness of about 0.25 inch (about 6.35 millimeter). For materialthicknesses greater than 0.25 inch, the threaded portion may have aseating torque of at least 400 inch-pounds. Alternatively, the threadedportion has seating torque of at least 600 inch-pounds, and may be atleast 800 inch-pounds measured using a ⅜ inch fastener having a flutedlead portion 68 having a nominal diameter between about 80% and 98% ofthe major diameter 58 and the threaded member having a materialthickness of about 0.25 inch (about 6.35 millimeter).

The self-drilling, thread-forming fastener 54 may be used in connectionssuch as shown in FIGS. 10A through 10C. A building member 84 used forbridging may be provided with one or more clearance holes 72 at each endlarger than the major diameter 58 of the fastener 54. In certainapplications, two bridging members 84 may be put together to form anextended length. In the past, bolting two bridging members 84 togetherrequired drilling a bolt hole through at least one of the members, oraligning pre-drilled holes to pass the bolt through for making abolt-and-nut connection. Aligning pre-drilled holes in the past was adisadvantage when the pre-drilled holes provided a length that wasdifferent than the desired length. Additionally, drilling bolt holes atthe job site added time and cost to the installation, reducingefficiency. The present bridging members 84 may be assembled togetherwithout drilling bolt holes at the job site. The self-drilling,thread-forming fastener 54 are installed through the clearance hole 72in the first building member 84 and the fluted lead portion 68 forms afastener opening in the second building member as the fastener 54 isrotated. The thread-forming portion 66 then forms threads in the bore ofthe fastener opening formed by the fluted lead portion, and continuedrotation of the fastener 54 clamps the first building member between thehead 63 and the threads formed in the second building member 84 as shownin FIG. 18B. For certain applications such as shown in FIG. 18C, a nut86 may be provided and threaded onto the fastener 54 and tightened asdesired. The self-drilling, thread-forming fastener 54 as shown in FIGS.18B and 18C may have a major diameter 58 between about ¼ inch and ⅜ inchas desired for the size and load requirements of the application. Thethreaded portion 64 of the thread-forming fastener 52 as shown in FIGS.18B and 18C typically comply with ASTM A307, ASTM A354, ASTM A325, orother fastener standards as desired.

As discussed above, the threaded portion 64 of the thread-formingfasteners 52 and self-drilling, thread-forming fastener 54, 56 mayinclude back-tapered threads, and may have a thread angle less than 60°.Alternatively, the thread angle may be less than 50°. In yet anotheralternative, the threads may have a thread angle between 45 and 50°. Theback-taper of the major diameter may be between about 0.0005 and 0.005inch per inch of axial length. Alternatively, the back-taper of majordiameter may be between about 0.001 and 0.003 inch per inch of length.In the past, the thread portion of fasteners used for buildingstructures typically had a pitch angle of 60°. We have found that thedrive torque required to drive prior self-tapping fasteners afterthread-forming was nearly the same as the thread-forming torque. This isa disadvantage because for larger fasteners, such as about ½ inch majordiameter fasteners and greater, an impact driver typically is requiredto drive the fasteners. While an impact driver delivers sufficienttorque to drive the prior fasteners, the time required to impact a largebolt into a structural member in the past was not commerciallypractical. The present fasteners 52, 54 may require an impact driver toprovide the thread-forming torque 74 to advance the thread-formingportion 66 into the fastener opening, but the drive torque 76 of thepresent fasteners is sufficiently lower than the thread-forming torque74 that the driver may easily turn the threaded portion 64 into thefastener opening without binding and engaging the impact mechanism. Withthe impact mechanism disengaged while installing the threaded portion,the fastener may be rapidly installed. Alternatively, the threading 74torque may be low enough that an impact driver is not required and adrill driver may be used.

The thread-forming fastener 52 and the self-drilling, thread-formingfastener 54 may be nutable, i.e., adapted to thread a nut on thefastener, such as the nut 86 shown in FIG. 18C. For a nut to be threadedonto the fastener 52, 54, the major diameter 58 of the thread-formingportion 66 may be about the same diameter or smaller than the majordiameter of the threaded portion 64. The thread profile of thethread-forming portion 66 corresponds to the threaded portion 64 toenable the nut to be threaded over the thread-forming portion.Additionally, for a nutable self-drilling, thread-forming fastener 54,the fluted lead portion 68 has a nominal diameter smaller than the minordiameter of the corresponding nut 86 such that the nut will pass overthe fluted lead portion 68.

In one alternative, the thread-forming fasteners 52 and theself-drilling, thread-forming fasteners 54 may be configured to be usedin place of bolt-and-nut fasteners without changing the hole sizes andhole placement in the building members. The major diameter of thethreaded portion 64 may be selected to be installed into standard-sizepunched or drilled holes provided in the building members. For example,a building connection designed for a ½ inch bolt-and-nut fastener may befabricated with punched holes having a diameter of 9/16 inch. Thethread-forming fasteners 52 and the self-drilling, thread-formingfasteners 54 may be configured to have a major diameter of ⅝ inch, or11/16 inch, or other major diameter providing thread engagement andseating torque as desired. By configuring the thread-forming fasteners52 and the self-drilling, thread-forming fasteners 54, fabricators cancontinue producing the building members using standard-size punches ordrills without costly re-tooling. It is contemplated that fasteners ofthis configuration may increase the capacity of the connection by 15% to30% over prior art standard nut-and-bolt fasteners through the same sizepilot hole, and in turn, can reduce the number of fasteners to carry thesame load by 15% to 30%.

For certain bolted connections, the threaded portion 64 of the fastenermust comply with fastener standards such as ASTM A307, ASTM A325, ASTMA354, ASTM A490, SAE J429 Grade 2, SAE J429 Grade 5, SAE J429 Grade 8,or other fastener standards. In the past, case hardened self-drillingfasteners and self-threading fasteners could not comply with thesestandards because of the case hardness of the prior fasteners. Priorfasteners were case hardened over the whole fastener reducing ductilityand preventing their use in many structural applications. The presentfasteners 52, 54 overcome some of the problems of the prior fasteners byselectively hardening portions of the fastener. Portions of the presentfasteners 52, 54 may be selectively hardened, such as the tapered leadportion 62, fluted lead portion 68, and the thread-forming portion 66 toa hardness of at least HRC 50. Additionally, between about 1 and 5threads between the threaded portion 64 and the thread-forming portion66 may be hardened to at least HRC 50. By hardening only a portion ofthe fastener to at least HRC 50, the portion of the threaded portion 64making the bolted connection may be provided with physical properties asdesired in compliance with ASTM A307, ASTM A325, ASTM A354, ASTM A490,SAE J429 Grade 2, SAE J429 Grade 5, SAE J429 Grade 8 or other selectedfastener standards. Typically, the fasteners 52, 54 are made with amedium carbon steel, medium carbon alloy steel, or a weathering steel inconformance with the desired fastener standard.

In one alternative, the floor joist system 100 may be a composite walland floor joist system such as disclosed in U.S. patent application Ser.No. 12/019,372, filed Jan. 24, 2008. The floor joist system 100 mayinclude the steel deck 42, fastened to the joists 40 usingself-drilling, thread-forming fasteners 56. Additionally, self-drilling,thread-forming stand-off screws 98 may be provided through the deck 42and joist 40 adapted to be encapsulated within the concrete slab 44providing a composite joist floor as disclosed in U.S. patentapplication Ser. No. 12/019,372.

The self-drilling, thread-forming stand-off screws 98 as shown in FIG.5E typically have a major diameter between about 0.12 inch and about ⅜inch. The self-drilling, thread-forming stand-off screws 98 may includethe head 63, a stand-off portion 69 having a desired length, a seatportion 61, the threaded portion 64 as discussed above adjacent the seatportion, and the thread-forming portion 66 as discussed above adjacentthe threaded portion 64 adapted to enable the fastener to engage withformed threads in a building member. The seat portion 61 may be a SEMSwasher positioned adjacent the stand-off portion 69. A SEMS washerincludes a washer or other member held captive on the fastener where thedimension of the fastener on each side of the SEMS washer being largerthan the washer hole prevents the SEMS washer from coming off.Alternatively, the seat portion may be a flange integral to thestand-off portion 69. In yet another alternative, the seat portion 61 ofthe self-drilling, thread-forming stand-off screws 98′ may include thehead. As shown in FIG. 5E, the self-drilling, thread-forming stand-offscrews 98′ may include an anchor member 102 formed integrally with thestand-off portion 69. The anchor member 102 may be a rolled collar asshown in FIG. 5E.

The seat portion 61 may include serrations 71 adjacent the threadedportion 64 to engage the surface of the steel deck 42 or other buildingmember during installation. The self-drilling, thread-forming stand-offscrews 98 has the fluted lead portion 68 as discussed above adjacent thethread-forming portion 66 with a nominal diameter between about 70 and95% of the major diameter 58 of the threaded portion adapted to form thefastener opening 70. The self-drilling, thread-forming stand-off screws98 is installed through the steel deck 42 into the joist 40 or otherbuilding member. The fluted lead portion 68 drills through the steeldeck 42 and joist, and the thread-forming portion 66 forms threads inthe bore of the drilled fastener opening for the threaded portion 64 toengage the joist 40. The self-drilling, thread-forming stand-off screws98 is tightened to clamp the deck 42 between the seat portion 61 and thethreads in the joist 40 or other building member.

As shown in FIGS. 16 and 17, the joists 40 may be connected to the loadbearing building member 110 such as the girder 46 using thread-formingfasteners 52. When connecting structural members using thethread-forming fasteners 52, the first member is provided with aclearance hole 72 larger in diameter than the major diameter of thefastener 52, and the second member is provided with the pilot hole 70smaller in diameter than the major diameter of the fastener, typicallybetween 80 and 98% of the major diameter 58, and typically larger thanthe minor diameter of the fastener 52. The joist 40 includes a joistseat 88 through which the joist 40 may be connected to the girder 46 orother load bearing member 110. As shown in FIGS. 16 and 17, variousconfigurations of joist seats may be used as desired. The joist seat 88includes one or more clearance holes 72 for fastening the joist to theload bearing member. To install the joist 40 to the girder 46 or otherload bearing member, the fastener 52 positioned in the clearance hole 72in the joist is driven into the pre-drilled hole 70 in the girder. Thethread-forming portion 66 forms threads in the hole 70 enabling thethreaded hole in the girder to act as a nut to clamp the joist seatbetween the girder and the head 63 of the fastener. Optionally, a nut 86may be provided and threaded onto the fastener 52 and tightened asdesired.

In the past, joists were fastened to the load bearing member by weldingor by a bolt-and-nut connection. The bolts used for fastening joiststypically comply with ASTM A307, A354, or A325. Bolt-and-nut connectionsrequire the installer to reach both sides of the connection to hold thenut while the bolt turns. Additionally, welded connections have been adisadvantage because a trained welder must be present and perform theweld connections. The presently disclosed thread-forming fasteners 52and self-drilling, thread-forming fastener 54 overcome these and otherdisadvantages, and may be installed from the top side of the joists 40.The present fasteners 52, 54 increase the speed of joist installationand decrease cost.

FIG. 19 shows a connection of a first structural building member 90having a first end plate 94, and a second structural building member 92having a second end plate 96. The second end plate is provided withpre-drilled pilot holes 70, and the first end plate is provided withpre-drilled clearance holes 72 for alignment with the pilot holes 70.The thread-forming fasteners 52 are provided through the clearance holes72 and are threaded into the pilot holes 70 of the second end plate 96.As the fastener 52 is tightened in the fastener opening, the second endplate 96 performs as a nut clamping the first end plate 94 between thehead 63 of the fastener and the threads formed in the second end plate96. Optionally, a nut may be threaded onto the installed fastener 52(not shown) as desired.

In the past, the end plate connection shown in FIG. 19 was typicallymade either by welding or a bolt-and-nut connection. The weld connectionrequires a trained welder and time to make the welds. The bolts used inend plate connections typically comply with ASTM A325, A354, or A490. Asdiscussed above, bolt-and-nut connections require the installer to reachboth sides of the connection to hold the nut while the bolt turns.Self-tapping fasteners in the past were unable to provide the threadforming capability while also complying with these fastener standards.

By contrast, the present thread-forming fasteners 52 may be installedfrom one side of the end plate connection, increasing the speed ofmaking the connection and decreasing cost. The fastener 52 in theapplication such as shown in FIG. 19 typically have a major diameterbetween about ½ inch and 1½ inch, or larger, as desired for the size andload requirements of the connection.

Certain structures require connection of a structural member to a loadbearing member using seat joints such as shown in FIGS. 20 and 21. Asshown in FIG. 20, the joist 40 may be connected to a column 116 using anangle bracket 120. The angle bracket 120 may be a right angle brackethaving an angled leg 122 and a support leg 124. The angled leg 122 mayinclude a plurality of clearance holes 72, and the support leg mayinclude pilot holes 70. As shown in FIG. 20, the column 116 has a columnflange 118 that may include pre-drilled pilot holes 70 for aligning withthe clearance holes 72. The pilot holes 70 in the support leg 124 may bepositioned for aligning with slots 126 in the joist 40. Thethread-forming fasteners 52 may be positioned through the clearanceholes 72 of the angle bracket 120 and driven into the pilot holes 70 inthe girder 46 to clamp the bracket 120 between the head 63 of thefastener and the threads formed in column flange 118 by fasteners 52.The joist 40 is connected to the support leg 124 by the thread-formingfasteners 52 into the bracket 120.

As shown in FIG. 21A, the load bearing member may be a hollow structuralsection (HSS) column 128. In the past, angle brackets were connected toa HSS column by welding (not shown), or using a through bolt 130 asshown in FIG. 21B or a clamp bracket 132 as shown in FIG. 21C. The priormethods of attaching to a HSS column have been expensive, timeconsuming, and for certain applications still often neededreinforcement. The present fasteners 52 form a robust connection of theangle bracket to the HSS column 128 in less time and less expense.

In an alternative configuration, the pilot holes in the column 116and/or HSS column 128 may be omitted and self-drilling, thread-formingfastener 54 used to fasten the angle bracket 120 to the load bearingmember under suitable load requirements. In this embodiment, thefastener 54 is installed through the bracket 120 into the column 128forming threads in the HSS column member. Optionally, the pilot holes inthe support leg 124 may also be omitted, and self-drilling,thread-forming fastener 54 used to fasten the joist 40 to the anglebracket 120 by forming threads in the angle bracket 120. Theself-drilling, thread-forming fastener 54 may have a major diameterbetween about ¼ and ½ inch as desired for the size and load requirementsof the application, and at least a portion of the threaded portion 64comply with fastener standard ASTM A307, A354, A325, A490, or otherfastener standard as required.

FIG. 22A shows two joists 40 longitudinally aligned in connection to thegirder 46 and having at least one tie plate 134. The tie plate 134 maybe provided with clearance holes 72 positioned as desired for assemblingthe tie plate to the top chord 140 of the joist 40. The self-drilling,thread-forming fastener 54 may be positioned through the clearance holes72 and drilled and thread-formed into the top chord 140.

Alternatively, as shown in FIG. 22B, a C-channel tie plate 135 may havean upper flange 136 and a lower flange 138 formed to fit between thejoist seat 88 and the top chord 140. The lower flange 138 includes pilotholes 70 positioned for aligning with clearance holes (not shown) in thegirder 46 and the joist seat 88. Thread-forming fasteners 52 are used toconnect the joist 40 to the girder 46 by positioning the thread-formingfastener 52 through the clearance holes 72 in the girder 46 and thejoist seat 88 and threading the thread-forming fastener 52 into thepilot hole 70 in the lower flange 138 of the C-channel tie plate 135.The thread-forming portion 66 of the thread-forming fastener 52 formsthreads in the bore of the pilot hole 70 in the tie plate 134, enablingthe tie plate 134 to act as a nut clamping the joist seat 88 against thegirder 46 as shown in FIG. 20. The top chord 140 of the joist is alsosecured to the upper flange 136 of the tie plate 134 usingself-drilling, thread-forming fastener 54. The top chord 140 may beprovided with clearance holes 72, through which the self-drilling,thread-forming fastener 54 may be fastened into the upper flange 136 ofthe C-channel tie plate 135 as shown in FIG. 20. Using theself-drilling, thread-forming fastener 54, no pilot holes are needed inthe upper flange 136 of the tie plate, simplifying manufacture andalignment of the tie plate 134 and reducing the installation time of thejoists.

In an alternative configuration, the thread-forming fasteners 52 may beprovided from above the joist seat and fastened into the girder when thespace between the top chord 140 and the joist seat 88 is sufficient toposition and drive the thread-forming fastener. In this alternative, thelower flange 138 of the tie plate includes clearance holes instead ofpilot holes, and the girder is provided with pilot holes instead ofclearance holes. The thread-forming portion 66 of the thread-formingfastener 52 forms threads in the girder 46 to clamp the joist seat 88between the tie plate 134 and the girder 46.

The thread-forming fastener 52 for the application shown in FIGS. 20through 24 may have a major diameter between about ⅜ inch and 1½ inch asdesired for the size and load requirements of the connection. At least aportion of the threaded portion 64 of the thread-forming fastener 52 asshown in FIGS. 20 through 24 may comply with ASTM A354, A325, A490, orother fastener standard as required.

The self-drilling, thread-forming fastener 54 for the application shownin FIGS. 20 through 24 may have a major diameter between about ¼ inchand ½ inch as desired for the size and load requirements of theconnection. The threaded portion 64 of the self-drilling, thread-formingfastener 54 as shown in FIGS. 20 through 24 may comply with ASTM A354,A325, A490, or other fastener standard as required.

The bottom chord 142 of the joist 40 may be connected to the loadbearing member, such as the girder 46, using a wide flange girder brace144 as shown in FIG. 25A. A first bracket 146 may be provided on thebottom chord, and a second bracket 148 may be provided on the girder 46,with the first bracket 146 and second bracket 148 provided with pilotholes for use with the thread-forming fasteners 52 for securing thebrace 144. The wide flange girder brace 144 may be connected between thefirst bracket 146 and second bracket 148 using thread-forming fasteners52. The wide flange girder brace 144 may be provided with slots 126through which the thread-forming fasteners 52 are installed into thepilot holes to fasten the wide flange girder brace 144 to the brackets.

Alternatively, the self-drilling, thread-forming fasteners 54 may beused to install the wide flange girder brace 144 to the brackets 146,148 such as shown in FIG. 25B. In this alternative, the first bracket146 and second bracket 148 are provided without pilot holes and the wideflange girder brace 144 may or may not be provided with clearance holesfor installing the self-drilling, thread-forming fastener 54.

The self-drilling, thread-forming fastener 54 and thread-formingfastener 52 as used in the application of FIGS. 25A and 25B may have amajor diameter between about ¼ inch and ½ inch, or larger as desired forthe size and load requirements of the connection. At least a portion ofthe threaded portion 64 of the fasteners 52, 54 as shown in FIGS. 25Aand 25B may comply with ASTM A307, A354, A325, A490, or other fastenerstandard as required.

Various building structures require bridging members or cross braces.The bridging members are typically used for bracing beams, trusses,joists, or other structural members to hold them together and in placeduring construction and to secure the structural members in place underbuilding loads and stresses. As shown in FIGS. 26 and 27, the floorjoist system 100 may include horizontal bridging members 150, diagonalbridging members 152, or both.

As shown in FIGS. 27 and 28, the ends of two bridging members 150, 152may be connected to an L-bracket 154 to secure a building member such asthe joist 40. As discussed above, under OSHA requirements forinstallation of double connections, the first member must be attachedbefore connection of the second member is commenced. In the past, asshown in FIG. 28A, a special two ended bolt 156 was provided for makingbridging double connections. An operator secured the first bridgingmember 152 by turning a nut 86 onto one end of the two ended bolt 156while holding the bolt 156 from turning. Then, the second bridgingmember was secured to the other end of the bolt 156 with a second nut86. The prior procedure was time consuming and costly. The presentfasteners 52, 54 may be used to quickly and efficiently secure bridgingmembers to the joists, reducing assembly time and cost duringinstallation.

The self-drilling, thread-forming fastener 54 as used in bridgingapplications may have a major diameter between about ¼ inch and ½ inchas desired for the size and load requirements of the connection. Thethread-forming fastener 52 as used in bridging applications may have amajor diameter between about ¼ inch and ⅝ inch, or larger as desired forthe size and load requirements of the connection. At least a portion ofthe threaded portion 64 of the fasteners 52, 54 used in bridging maycomply with ASTM A307, A354, A325, A490, or other fastener standard asrequired.

The present fasteners 52, 54 provide an efficient, more robust and lessexpensive way to install bridging. As shown in FIG. 28B, the L-bracket154 may be provided with a pilot hole 70, and the bridging member 150,152 provided with the slot 126 or clearance hole 72. The thread-formingfastener 52 may be provided through the clearance hole 72 andthread-formed into the L-bracket 154 as shown in FIG. 29, clamping thebridging member 150, 152 onto the L-bracket 154. Then, a second bridgingmember having a clearance hole 72 may be provided over the end of thefastener 52, as shown in FIG. 28B, and the nut 86 threaded onto thefastener 52 to secure the second bridging member as shown in FIG. 30.

Alternatively, the L-bracket 154 may be provided without a pilot hole,and the self-drilling, thread-forming fastener 54 may be used to securethe first bridging members to the L-bracket as shown in FIG. 28C, andthe nut 86 threaded onto the fastener 54 to secure the second bridgingmember.

A further advantage of the presently disclosed bridging assembly isshown in FIG. 31. Under current OSHA regulations, certain joists requirebridging to be installed during erection. (See Perry S. Green and TimHoltermann, Bridging of Open-Web Steel Joists and Joist Girders, ASCEConf. Proc. 314, 110 (2008)). For such joist installations, the crane orother lift setting the joists cannot release the joist until diagonalbridging is secured in place. In the past, securing erection bridgingusing the bolt 156 as shown in FIG. 28A required the crane operator towait until the bolts 156 and nuts were secured by operators working onthe structure or in lifts. The prior installation used valuable craneoperation time inefficiently. Using the present fasteners 52, 54, thebridging members are connected and secured quickly and efficiently,using electric or pneumatic drill drivers enabling the crane operator torelease the hoisting cables from the joist more quickly, and reducingerection time cost of the building structure.

FIG. 32 shows the diagonal bridging members 152 in a chevronconfiguration between two horizontal bridging members 150. The diagonalbridging members 152 may be provided with a slot or clearance hole ateach end. The self-drilling, thread-forming fastener 54 may be used tosecure the diagonal bridging members 152 to the horizontal bridgingmembers 150.

In the past, the chevron bridging configuration of FIG. 32 with open webjoists required pre-drilling or pre-punching holes either duringfabrication of the horizontal bridging members 150 or at theconstruction site. Pre-drilling the horizontal bridging members 150 hasnot been commercially practicable because of the additional time andinefficiency caused at the job site. Additionally, factory pre-drillingrequires the installers to use certain horizontal bridging members 150in certain locations for hole alignment, which also requires additionaltime and coordination on the job site. The present self-drilling,thread-forming fasteners 54 enable the operator to rapidly install thediagonal bridging members 152 in a chevron bridging configuration orother configuration wherever the bridging is needed without pre-drillingholes in the horizontal bridging members 150. Optionally, the diagonalbridging members 152 may be installed with the present self-drilling,thread-forming fasteners 54 without pre-drilling holes in the horizontalbridging members 150 or the diagonal bridging members 152 by installingthe self-drilling, thread-forming fasteners 54 through both thehorizontal and diagonal bridging members.

Horizontal bridging members 150 are typically secured to a wall or otherstructure as shown in FIG. 33. In the past, a support bracket wassecured to a wall or other structure using fastening methods known inthe art, such as masonry screws 159 or other fasteners. With the presentdisclosure, a support bracket 158 may include clearance holes (notshown) through which self-drilling, thread-forming fastener 54 may beinstalled. The horizontal bridging member 150 can be cut to a desiredlength and secured to the support bracket 158 using self-drilling,thread-forming fasteners 54.

Metal building systems may include various rigid frame configurations.The present self-drilling, thread-forming fastener 54 and thread-formingfasteners 52 may be used to form a variety of structural connectionsrapidly that are very robust and secure. As shown in FIG. 34, a rigidframe knee joint 160 may include a column member 162 and a rafter member164. The column member 162 includes a butt plate 166 positioned to forma connection with the rafter member 164. The rafter member 164 includesan end plate 168 corresponding to the butt plate 166 for making a boltedconnection. Either the end plate 168 or the butt plate 166 may beprovided with pilot holes, and the other provided with clearance holespositioned for alignment with the pilot holes and sized for thethread-forming fastener 52. To make the structural connection, thethread-forming fastener 52 may be provided through the clearance holeand turned to form threads in the bore of the pilot hole as discussedabove. As shown in FIGS. 34 and 34A, the rafter member 164 may be bracedby one or more girder braces 144 between bracket 148 and a purlin 172.

In rigid frame connections as shown in FIG. 34, the threaded portion 64of the thread-forming fastener 52 typically are sized as desired for thesize and load requirements of the connection, but may have a majordiameter 58 between about ½ and 1½ inch, or larger, and at least aportion may comply with fastener standard ASTM A325 or ASTM A490. In thepast, the only way to achieve a secure connection was by using a weldconnection or a bolt and corresponding nut. By using the presentdisclosure, the connection may be made by driving the thread-formingfastener 52 from one side of the connection using an electric orpneumatic drill driver. The present thread-forming fastener 52 may beused to clamp the first member between the head 63 of the fastener 52and the formed threads in the second member such that the thread-formedsecond member acts as a nut. In certain applications, a nut may still bedesired on the fastener 52, particularly where additional pieces aresecured using the same connection. In that case, nuts may be turned ontothe threaded portion 64 of fasteners 52 and tightened at less intensiveperiods during the erection of the building since the thread-formingfasteners 52 already form the structural connection by tightening intothe threaded plate 168.

As shown in FIGS. 34 and 34A, rigid frame structures include a pluralityof purlins 172 for supporting the roof covering (not shown). Gifts 174are provided for supporting wall sheeting (not shown) on the sides ofthe structure. An eave strut 176 may be provided adjacent the roof edge.The self-drilling, thread-forming fastener 54 may be used to provide asecure connection of purlins 172, gifts 174, and eave struts 176 to theframe. The self-drilling, thread-forming fastener 54 may have a majordiameter between about ¼ and ½ inch as desired for the size and loadrequirements of the application, and at least a portion of the threadedportion 64 comply with fastener standard ASTM A307, A354, A325 or otherfastener standard as desired.

Purlin clips 173, such as shown in FIGS. 40 and 42A through 42C, may beconnected to the rafter member 164 and the purlins 172 connected to thepurlin clips 173 using thread-forming fasteners 52 or self-drilling,thread-forming fasteners 54. Additionally, as shown in FIGS. 34 and 34A,girt clips 175 may be connected to the column member 162 and the girts174 connected to the girt clips 175 using thread-forming fasteners 52 orself-drilling, thread-forming fasteners 54. The purlin clips 173 andgirt clips 175 may include pilot holes positioned for installation ofthread-forming fasteners 52 or self-drilling, thread-forming fastener54. Pilot holes may be provided in the column member 162 and the raftermember 164 for connecting the purlins 172, girts 174, and eave struts176. The purlins 172, girts 174, and eave struts 176 may be providedwith clearance holes positioned for alignment with the pilot holes inthe corresponding clips 173, 175, column member 162 and rafter member164 during installation of fasteners 52 or 54. Thread-forming fasteners52 may be positioned through the clearance holes and thread-formed intothe pilot holes for connecting the members to the frame. Alternatively,when using self-drilling, thread-forming fasteners 54, the purlins 172and girts 174 may be provided without clearance holes, and the purlinclips 173 and girt clips 175 provided without pilot holes, and theself-drilling, thread-forming fasteners 54 installed by drilling andthread-forming through the purlin or girt and clip. The fasteners 52, 54for installing purlins 172, girts 174, and eave struts 176 may have amajor diameter of ½ inch and at least a portion of the threaded portion64 satisfy fastener standard ASTM A307, A354, or A325. Alternatively themajor diameter 58 may be between about ⅜ and 1 inch, as desired for thesize and load requirements of the connection.

The column member 162 may be braced by one or more wide flange girderbraces 144 between bracket 148 and a girt 174 using self-drilling,thread-forming fastener 54. As shown in FIG. 34A, the rafter member 164may be braced by one or more wide flange girder braces 144 betweenbracket 148 and a purlin 172 using self-drilling, thread-formingfastener 54.

As shown in FIGS. 35 through 37, girts 174 may be connected to columnmember 162 using girt clips 175 using self-drilling, thread-formingfasteners 54. The girt clip 175 may be attached to the column 162 usingself-drilling, thread-forming fastener 54 as shown in FIGS. 35 through37. The girt clip 175 may be an L-bracket having clearance holes on thefirst leg of the L-bracket through which the self-drilling,thread-forming fastener 54 may be installed into the column member 162.The girts 174 may be fastened to the girt clip 175 through the secondleg of the L-bracket using self-drilling, thread-forming fastener 54.The girt clip 175 may have no pre-drilled holes on the second leg of theL-bracket, and the self-drilling, thread-forming fastener 54 may drilland install through both the girt 174 and the girt clip 175. In FIG. 35,the girt clip 175 may be installed onto the column member 162, andsupport a lapped connection of two girts 174. To form the lappedconnection, the end of one girt 174 overlaps the end of a second girt174 and is fastened together with self-drilling, thread-forming fastener54 or thread-forming fasteners 52 as described above. Alternatively, thecolumn member 162 may be provided to the construction site with girtclips 175 welded in place. In yet another alternative, girt clips may beomitted by bolting the girts 174 directly to the column member 162 (notshown).

In the applications of FIGS. 35 and 37, the girt clips 175 are attachedto the web of a girder in a double connection. The first girt clip 175may be installed using self-drilling, thread-forming fastener 54 orthread-forming fasteners 52 as desired to the girder web 180. Then, thesecond girt clip may be positioned over the ends of the fasteners 52,54, and secured to the girder web 180 using nuts 86. A girt 174 may befastened to each girt clip 175 as desired as shown in FIGS. 35 and 37.

A girt corner connection, shown in FIG. 38, may be made using a girt tieclip 182 having clearance holes for installing self-drilling,thread-forming fastener 54 through. The self-drilling, thread-formingfasteners 54 may be provided through the clearance holes in the girt tieclip 182 and installed into the girts 174.

In certain applications, a plurality of girts 174 may be nested togetherfor increased strength. As shown in FIG. 39, a girt 174 may be placedover a second girt 174′ and fastened using a plurality of self-drilling,thread-forming fastener 54. Similarly, purlins may be nested (notshown), and eave struts may be nested (not shown), secured usingself-drilling, thread-forming fastener 54 as described above.

As shown in FIG. 40, for certain sloped roof applications, a girt 174may be installed adjacent the roof on the high eave using self-drilling,thread-forming fasteners 54.

The purlins 172, girts 174, and eave struts 176 may be provided inlengths shorter than required, and connected to form desired lengths.Typically, purlins 172, girts 174, and eave struts 176 are formed ofsheet metal having steel thicknesses between about 10 gage and 16 gage.As shown in FIG. 41, two purlins 172 may be overlapped and fastened withself-drilling, thread-forming fastener 54 as described above. In onealternative, the purlins 172 may make a lapped connection at a purlinclip 173 as shown in FIG. 42A, and at least one end of the purlin 172may be provided with a plurality of clearance holes larger than themajor diameter 58 of the fastener 54, positioned for making a lappedconnection. To connect the members in a lapped connection as shown inFIGS. 41 and 42A, clearance holes of one member are lapped over a secondmember, and the self-drilling, thread-forming fastener 54 are positionedthrough the clearance holes and drilled and thread-formed into thesecond member and/or the purlin clip 173. Alternatively, clearance holesmay be omitted and the self-drilling, thread-forming fastener 54 drilledand thread-formed into the first and second member. For sheet metalconnections between about 10 gage and 14 gage, the major diameter of theself-drilling, thread-forming fastener 54 may be between about 0.19 inch(such as a #10 fastener, ASME B1.1 Unified Inch Screw Thread Standard)and ½ inch. The threaded portion 64 may comply with fastener standardA307, A325, A354, or other fastener standard as desired.

As shown in FIG. 42A, the purlin clip 173 may be an L-bracket havingclearance holes on the first leg of the L-bracket through which theself-drilling, thread-forming fastener 54 may be installed into therafter member 164. The purlin 172 may be fastened to the purlin clip 173through the second leg of the L-bracket using self-drilling,thread-forming fastener 54. The purlin clip 173 may have no pre-drilledholes on the second leg of the L-bracket, and the self-drilling,thread-forming fastener 54 may drill and thread-form through both thepurlin 173 and the purlin clip 173. As shown in FIG. 42B, the purlinclips 173 may be omitted and the purlins 172 connected to the raftermember 164. In yet another alternative, the rafter members 164 may beprovided to the construction site with purlin clips 173 welded in placeas shown in FIG. 42C.

FIG. 43 shows a purlin connection made with self-drilling,thread-forming fastener 54 in a roof valley. A valley rafter 184 may beprovided with purlin clips 173 installed by welding. Alternatively,purlin clips 173 may be fastened to the valley rafter 184 usingself-drilling, thread-forming fastener 54. In any event, a valley clip186 is provided having a shape adapted to connect the end of one or morepurlins 172 to the valley rafter 184. The valley clip 186 as shown inFIG. 43 includes a clip mounting portion 188. The self-drilling,thread-forming fastener 54 may be installed through the purlin clip 173and the clip mounting portion 188 to secure the valley clip 186 to therafter 184. The valley clip includes at least one purlin tab 190. Theself-drilling, thread-forming fastener 54 may be provided through thepurlin tab 190 and the purlin 172 to install the purlin 172 to thevalley clip 186. Clearance holes may be provided in either the purlins172 or purlin clip 173 as desired to install the purlin 172 to thepurlin clip 173, and either the valley clip 186 or purlin clip 173 asdesired to install the valley clip 186 to the purlin clip 173.

Panel clips 178 may be attached to purlins 172 using self-drilling,thread-forming fastener 54. The panel clips 178 may be provided withclearance holes larger than the major diameter 58 of the fastener 54.The self-drilling, thread-forming fastener 54 are installed through theclearance holes and drilled and threaded into the purlin 172 as shown inFIG. 34A.

FIGS. 44 and 45 show connections of a door jamb 192 to a girt 174 andrafter member 164. As shown in FIG. 44, the jamb 192 is fastened to jambclip 194 using self-drilling, thread-forming fastener 54. The jamb clip194 may be fastened to the girt 174 using self-drilling, thread-formingfastener 54. The jamb clip 194 may be shaped for installing to a raftermember using self-drilling, thread-forming fastener 54 as shown in FIG.45. The jamb clip 194 may or may not include clearance holes forinstalling the self-drilling, thread-forming fastener 54 into the girt174 or rafter member 164. The door jamb 192 may or may not be providedwith clearance holes for installing the self-drilling, thread-formingfastener 54 into the jamb clip 194. Alternatively, pilot holes may beprovided in the jam clip 194 and thread-forming fasteners 52 may beprovided to attach the door jamb 192 to the jamb clip 194.

Other structural connections may be made using the thread-formingfasteners 52 and/or self-drilling, thread-forming fastener 54 as shownin FIGS. 46 through 61. An alternative structural knee joint 170 isshown in FIG. 46. The column member 162 is connected to the raftermember 164 using thread-forming fasteners 52. In the configuration ofFIG. 46, the butt plate 166 is provided with pilot holes and the endplate 168 is provided with clearance holes 72, and the thread-formingfasteners 52 are threaded into the butt plate.

FIG. 47 shows the rafter member 164 supported by an interior column 196.The interior column 196 has a top plate 198 provided with clearanceholes 72. In the application of FIG. 47, the rafter member 164 includesa bottom flange 200 having pilot holes corresponding in location withthe clearance holes in the top plate 198 of the column 196.Thread-forming fasteners 52 may be positioned through the clearanceholes 72 and thread-formed into the bottom flange 200 to connect thecolumn 196 to the rafter member 164. Alternatively, the top plate 198may be provided with pilot holes and the bottom flange 200 withclearance holes, and the thread-forming fasteners 52 may be installedthrough the clearance holes 72 in the bottom flange 200 andthread-formed into the top plate 198 to connect the column 196 to therafter member 164.

Shown in FIG. 48, mezzanine members 202 may be supported by the interiorcolumn 196. The mezzanine members 202 have a bottom flange 200 providedwith clearance holes 72 corresponding in location with pilot holes inthe top plate 198. Thread-forming fasteners 52 may be installed throughthe clearance holes 72 in the bottom flange 200 and thread-formed intothe top plate 198 to connect the column 196 to the mezzanine members202. Alternatively, the bottom flange 200 may be provided with pilotholes corresponding in location with clearance holes in the top plate198 of the column 196. Thread-forming fasteners 52 may be providedthrough the clearance holes 72 and threaded into the bottom flange 200to connect the mezzanine members 202 to the column 196.

Alternatively, the mezzanine members 202 may be connected to the web 180of the interior column 196 in a double connection such as shown in FIG.49A. To comply with OSHA securement requirements, the first mezzaninemember 202 must be secured to the column 196 before connecting thesecond mezzanine member 202′. In the past, weld connections orbolt-and-nut connections 204 such as shown in FIG. 49C, had to be madeto hold the first member 202. The OSHA securement bolt and nutconnection had to be positioned to not interfere with the structuralconnection. As shown in 41C, this required unique parts for the left andright sides of the connection. We have found that the OSHA requirementscan be achieved using thread-forming fasteners 52 using the samecomponents on both sides of the double connection as desired such asshown in FIG. 49A.

As shown in FIGS. 49A and 49B, at least one mounting bracket 206 isattached to each mezzanine member 202. The mezzanine members 202 may beprovided to the construction site with the mounting brackets 206 weldedin place. Alternatively, the mounting brackets 206 may be fastened tothe mezzanine members 202 using self-drilling, thread-forming fastener54 or thread-forming fasteners 52 as desired. In any event, the mountingbracket may be provided with clearance holes 72 larger than the majordiameter of the fastener 54 for installing the self-drilling,thread-forming fastener 54. To secure the first mezzanine member 202,the self-drilling, thread-forming fastener 54 may be positioned throughthe clearance holes 72 in the bracket 206 and drilled and thread-formedinto the web 180 of the interior column 196. As installed, theself-drilling, thread-forming fastener 54 is threaded into the web 180to a desired seating torque, securing the mezzanine member 202 to thecolumn without need for extraneous fasteners 204. Then, the clearanceholes of the mounting bracket 206 of the second mezzanine member 202′are positioned over the ends of the installed self-drilling,thread-forming fastener 54 on the opposite side of the web 180, and nuts86 may be tightened onto the self-drilling, thread-forming fastener 54to clamp the second mounting bracket 206 against the web 180.Alternatively, pilot holes are pressed in the web corresponding to theclearance holes 72 in the mounting brackets so the thread-formingfastener 52 may be positioned through the bracket 206 and the web 180 ofthe interior column 196. Thus, the mezzanine members 202 are securedusing thread-forming fasteners 52. The self-drilling, thread-formingfastener 54 for the application of FIG. 49A may have between about ¼ and½ inch major diameter as desired for certain load requirements.Alternatively, the thread-forming fasteners 52 for the application ofFIG. 49A may be between about ¼ and 1½ inch, or larger, in majordiameter for load requirements as desired.

Alternatively, mezzanine members 202 may be connected to the flanges ofcolumn 196 as shown in FIG. 50. In this application, the flanges ofcolumn 196 may be provided with pilot holes corresponding to clearanceholes in the mounting bracket 206. The thread-forming fasteners 52 maybe provided through the clearance holes in the mounting bracket 206 andinstalled into the pilot holes in the column flanges.

FIG. 51 shows rafters 228 connected to the flanges of column 196. Atleast one mounting bracket 206 is attached to each rafters 228. Therafters 228 may be provided to the construction site with the mountingbrackets 206 welded in place. Alternatively, the mounting brackets 206may be fastened to the rafters 228 using self-drilling, thread-formingfastener 54 or thread-forming fasteners 52 as desired. In either case,the mounting bracket 206 may be provided with clearance holes 72 largerthan the major diameter of the fastener 54 for installing thethread-forming fasteners 52 to the column 196. In this application, theflanges of column 196 may be provided with pilot holes corresponding tothe clearance holes in the mounting bracket 206. The thread-formingfasteners 52 may be installed through the clearance holes in themounting bracket 206 and thread-formed into the pilot holes in thecolumn flanges. Alternatively, the pilot holes may be omitted from theflanges of the column 196 and self-drilling, thread-forming fastenersused to connect the mounting brackets 206 and the rafters 228 to thecolumn. The self-drilling, thread-forming fastener 54 for theapplication of FIG. 51 may be between about ¼ and ½ inch major diameteras desired for certain load requirements. Alternatively, thethread-forming fasteners 52 for the application of FIG. 51 may bebetween about ¼ and 1½ inch, or larger, major diameter fasteners forload requirements as desired.

Alternatively the rafter 228 may be provided with the end plate 168 asshown in FIG. 52, and fasteners 52, 54 as desired installed through theend plate 168 as discussed above with reference to FIGS. 34 and 46.

FIG. 53 shows an expandable endwall connection including the columnmember 162 having an outside flange 218 and an endwall stub 216 havingan inside flange 220. The outside flange 218 of the column member 162may be provided with pilot holes to install thread-forming fasteners 52.The inside flange 220 of the endwall stub 216 may be provided withclearance holes larger than the major diameter of the fastener 52located corresponding to the pilot holes in the outside flange 218. Thethread-forming fasteners 52 may be provided through the clearance holesand installed into the pilot holes in the outside flange 218.Optionally, nuts 86 may be provided on the ends of the thread-formingfasteners 52. Alternatively, the pilot holes may be provided in theinside flange 220 and clearance holes in the outside flange 218, and thethread-forming fasteners 52 threaded into the inside flange 220. In yetanother alternative, the pilot holes may be omitted and self-drilling,thread-forming fasteners 54 used to connect the endwall stub 216 to thecolumn member 162. A right-angle impact driver may be used to drive thethread-forming fasteners 52 for certain applications when clearancebetween the beam flanges is limited. The self-drilling, thread-formingfastener 54 for the application of FIG. 53 may be between about ¼ and ½inch major diameter as desired for certain load requirements.Alternatively, the thread-forming fasteners 52 for the application ofFIG. 53 may be between about ¼ and 1½ inch, or larger, major diameterfor load requirements as desired.

The endwall stub 216 may be connected to an endwall bracket 222 attachedto the web 224 of the rafter member 164. The endwall bracket 222 may beprovided with pilot holes and the web 224 provided with clearance holesthrough which the self-drilling, thread-forming fastener 54 may bethread-formed into the endwall bracket 222. Then, the inside flange 220may be connected to the endwall bracket 222 using thread-formingfasteners 52 or self-drilling, thread-forming fastener 54 as desired. Incertain applications, the connection between the endwall bracket 222 andthe inside flange 220 may be tightened to a low torque about equal tohand tightening, with a nut 86 tightened on the back of the bracket 222to lock the fastener 52, 54 in place. Alternatively, the nut 86 may beomitted and a burr formed on the fastener 52, 54 on the back side of thebracket 222 to lock the fastener 52, 54 in place. As shown in FIG. 53,the rafter member 164 may be braced by one or more wide flange girderbraces 144 between bracket 148 and a purlin 172 using self-drilling,thread-forming fastener 54. Self-drilling, thread-forming fastener 54may be used to install a rake angle 226 along the end of the purlins172.

In certain building applications, an eave extension beam 230 may beconnected to the column member 162. As shown in FIG. 54, the columnmember 162 may include an upper flange 232, which may include pilotholes for connecting the eave extension beam 230. The eave extensionbeam 230 may include clearance holes larger than the major diameter ofthe fastener 52 located corresponding to the pilot holes in the upperflange 232. The thread-forming fasteners 52 may be positioned throughthe clearance holes and thread-formed into the pilot holes in the upperflange 232 to secure the eave extension beam 230 to the column member162. Alternatively, for certain load requirements, the pilot holes maybe omitted and self-drilling, thread-forming fastener 54 provided toconnect the eave extension beam 230 to the column member 162. In anyevent, nuts 86 may be tightened onto the fasteners 52, 54 (not shown) tofurther secure the eave extension beam 230 as desired.

An eave strut clip 234 may be attached to the eave extension beam 230using self-drilling, thread-forming fastener 54 as shown in FIG. 54. Theeave strut clip 234 may be an L-bracket having clearance holes on thefirst leg of the L-bracket through which the self-drilling,thread-forming fastener 54 may be installed into the eave extension beam230. The eave strut 176 may be fastened to the eave strut clip 234through the second leg of the L-bracket using self-drilling,thread-forming fastener 54. The eave strut clip 234 may have nopre-drilled holes on the second leg of the L-bracket, and theself-drilling, thread-forming fastener 54 may drill and thread-formedthrough both the eave strut 176 and the eave strut clip 234.

Also shown in FIG. 54, box beam members 236 may be provided adjacent theeave. The box beam members 236 may be fastened to the eave extensionbeam 230 using self-drilling, thread-forming fastener 54 as installationspace permits. In certain applications, bolt-and-nut connections may beused when insufficient clearance for a right-angle impact driver.

FIG. 55A shows a double connection of diagonal bracing requiring OSHAsecurement. The diagonal braces 214 of FIG. 55A may be connected to agusset 212. The gusset 212 may be secured between a column 208 and abeam member 210. As shown in FIG. 55B, a diagonal brace 214 may beprovided on each side of the gusset 212. In the past, to secure adiagonal brace on each side of the gusset, OHSA securement requirementsrequired that the first diagonal brace 214′ be secured before attachingthe second diagonal brace 214. As shown in FIG. 55C, this requiredadditional clearance holes through the first diagonal brace 214′ to makea bolt-and-nut connection to the gusset 212 without interfering with theconnection of the second diagonal brace 214. We have found that the OSHArequirements can be achieved using self-drilling, thread-formingfastener 54 as shown in FIG. 55B using the same diagonal brace 214 onboth sides of the gusset as desired.

As shown in FIGS. 55A and 55B, each diagonal brace 214 may be providedwith clearance holes 72 larger than the major diameter of the fastener54. The self-drilling, thread-forming fastener 54 may be providedthrough the clearance holes 72 in the diagonal brace 214 and installedinto the gusset 212. Once installed, the self-drilling, thread-formingfastener 54 is thread-formed into the gusset 212 and tightened to adesired seating torque, securing the first diagonal brace 214 to thegusset without need for extraneous fasteners 204. Then, the clearanceholes of the second diagonal brace 214 are positioned over the ends ofthe installed self-drilling, thread-forming fastener 54 on the oppositeside of the gusset 212, and nuts 86 tightened onto the self-drilling,thread-forming fastener 54 to clamp the second diagonal brace 214against the gusset 212. Alternatively, pilot holes positionedcorresponding to the clearance holes 72 in the diagonal braces 214 maybe provided through the gusset 212. Then, the diagonal braces 214 may besecured to the gusset 212 using thread-forming fasteners 52. Thethread-forming fasteners 52 for the application of FIG. 55A may befasteners 52 of 1 inch major diameter. Alternatively, the thread-formingfasteners 52 for the application of FIG. 55A may be between about ¼ and1½ inch, or larger, major diameter for load requirements as desired. Inapplications where the self-drilling, thread-forming fastener 54 may beused, the self-drilling, thread-forming fastener 54 for the applicationof FIG. 55A may be between about ¼ and ½ inch major diameter as desiredfor certain load requirements. The diagonal bracing 214 may have anydesired cross sectional shape, such as U-channel as shown in FIG. 55A,L-channel as shown in FIG. 56, or other sectional shapes as desired.

FIG. 56 shows an alternative bracing configuration having diagonalbracing 214 and a pipe strut 238 installed between two columns 196. Astrut bracket 240 is provided on the web 180 of each column 196 as shownin FIGS. 56 and 57. The pipe strut 238 typically is provided to theconstruction site with a mounting plate 242 welded in place on each endof the pipe strut 238. Alternatively, the mounting plates 242 may befastened to the strut 238 using thread-forming fasteners 52 as desired.The strut bracket 240 is provided with pilot holes adapted forinstalling thread-forming fasteners 52, and the strut mounting plates242 provided with clearance holes larger than the major diameter of thefasteners 52 and positioned to correspond with the pilot holes in thestrut bracket 240. Thread-forming fasteners 52 may be provided throughthe clearance holes and thread-formed into the pilot holes in the strutbracket. The thread-forming fasteners 52 may have a major diameter 58 of1 inch. Alternatively, the thread-forming fasteners 52 may have a majordiameter 58 between about ¼ inch and 1½ inch as desired for loadrequirements. Alternatively, the pilot holes may be omitted from thestrut brackets 240 and self-drilling, thread-forming fastener 54 used toconnect the mounting plates 242 to the strut brackets 240 as desired forparticular load requirements.

As shown in FIG. 56, diagonal bracing may form an X between the columns196. At least one diagonal brace 214 may extend from the gusset 212 inan upper corner to the gusset 212 in an opposite lower corner. Theopposing diagonal brace 214 may include a splice plate 244 where thediagonal braces cross. As shown in FIG. 56, a piece of the diagonalbrace 214 may extend from the gusset 212 in an upper corner to thesplice plate 244 in the center of the X-bracing, and a second diagonalbrace 214 may extend from the spice plate 244 to the gusset 212 in theopposite lower corner. The splice plate 244 may be provided with pilotholes, and the ends of the diagonal brace 214 provided with clearanceholes larger than the major diameter of the fasteners 52. Thethread-forming fastener 52 may be positioned through the clearance holeand thread-formed into the pilot holes in the splice plate 244.Alternatively, the pilot holes in the splice plate 244 may be omittedand self-drilling, thread-forming fastener 54 may be used to install thediagonal brace 214 to the splice plate 244. A diagonal brace 214 may beinstalled on each side of the gusset 212 in a double connection asdiscussed above with reference to FIG. 55A. Alternatively, the diagonalbrace may be installed on one side of the gusset 212 usingthread-forming fasteners 52 or self-drilling, thread-forming fastener 54as desired.

Typically, metal building structures include bracing for wind loads. Asshown in FIG. 58, a C-channel brace strut 246 may be connected to abrace strut bracket 250 connected to a wind column 248, the C-channelbrace strut 246 extending adjacent the bottom chord of a plurality ofjoists 40. The C-channel brace strut 246 may be provided with clearanceholes through which self-drilling, thread-forming fastener 54 may fastenthe C-channel brace strut 246 to the brace strut bracket 250. The bracestrut bracket 250 may be fastened to the wind column 248 usingself-drilling, thread-forming fastener 54. Alternatively, the windcolumn 248 may be drilled with pilot holes, and the brace strut bracket250 may have clearance holes corresponding with the pilot holes throughwhich thread-forming fasteners 52 may be installed to fasten the bracestrut bracket 250 to the wind column. The bottom chords 142 may beconnected to the C-channel brace strut 246 with self-drilling,thread-forming fastener 54.

Brace clips 252 may be fastened to the C-channel brace strut 246 usingself-drilling, thread-forming fastener 54 as shown in FIGS. 58 and 59.Braces 254 such as shown in FIGS. 59A and 59B are connected to the braceclips 252 and secured to columns or rafters as known in the art forbracing wind loads (not shown).

FIGS. 60A and 60B are views showing a purlin transition connection. Insome applications, a second portion of a roof structure may be addedadjacent the ends of purlins 172 of a first portion of roof structure.As shown in FIG. 60A, purlins 172 are installed above a rafter member164. A transition purlin 256 may be attached traverse to the ends of thepurlins 172 of the first portion of roof structure adapted to securepurlins 172′ of the second portion of roof structure. L-brackets 258 maybe used to connect the transition purlin 256 to the ends of the purlins172 as shown in FIGS. 60A and 60B. The L-bracket 258 may be attached tothe purlins using self-drilling, thread-forming fasteners 54. Clearanceholes may or may not be provided in the clearance bracket for installingthe self-drilling, thread-forming fasteners 54 into the purlin 172. Theself-drilling, thread-forming fasteners 54 may be installed through thetransition purlin 256 into the L-bracket 258 to secure the transitionpurlin 256 to the L-bracket and purlins 172. The L-brackets 258 may beprovided to secure the purlins 172′ of the second portion of roofstructure to the transition purlin 256. Clearance holes may or may notbe provided in the clearance bracket for installing the self-drilling,thread-forming fasteners 54 into the transition purlin 256. Theself-drilling, thread-forming fasteners 54 may be installed through thepurlin 172′ into the L-bracket 258 to secure the purlin 172′ to theL-bracket and the transition purlin 256.

The self-drilling, thread-forming fasteners 54 or thread-formingfasteners 52 may be used for installing a parapet as shown in FIG. 61. Aparapet stub 260 may have an inside flange 262 and the column member 162with outside flange 218. The inside flange 262 of the parapet stub 260may be provided with clearance holes larger than the major diameter ofthe fastener 54 positioned for installing self-drilling, thread-formingfasteners 54 into the outside flange 218. Alternatively, the outsideflange 218 of the column member 162 may be provided with pilot holes toinstall thread-forming fasteners 52 into the pilot holes in the outsideflange 218. Optionally, nuts 86 may be provided on the ends of thethread-forming fasteners 52 or self-drilling, thread-forming fasteners54. Alternatively, clearance holes may be provided in the outside flange218 and the fasteners 52 or 54 thread-formed into the inside flange 262.A right-angle impact driver may be used to drive the fasteners 52, 54for certain applications when clearance between the beam flanges islimited. The self-drilling, thread-forming fastener 54 for theapplication of FIG. 61 may be between about ¼ and ½ inch major diameteras desired for certain load requirements. Alternatively, thethread-forming fasteners 52 for the application of FIG. 61 may bebetween about ¼ and 1½ inch, or larger, major diameter for loadrequirements as desired.

A C-girt 264 may extend between two or more parapet stubs 260, theC-girt 264 installed into an upper portion of the parapet stub 260 usingself-drilling, thread-forming fasteners 54. Additionally, girts 174 maybe secured to the parapet stub 260 and the column member 162 asdiscussed above. Self-drilling, thread-forming fastener 54 may be usedto install a rake angle 226 along the end of the purlins 172.

A fascia may include a plurality of fascia vertical members 266 such asshown in FIG. 62. The self-drilling, thread-forming fasteners 54 orthread-forming fasteners 52 may be used for installing the fascia. Oneor more spacer members 270 may be provided to install the fascia adesired distance from the column member 162. Each spacer may include afirst end plate 272, and a second end plate 274 having clearance holes.As shown in FIG. 62, self-drilling, thread-forming fasteners 54 may beinstalled through clearance holes in the outside flange 218 of thecolumn member 162 and thread-formed into the first end plate 272. Thefascia vertical members 266 may have an inside flange 268, andself-drilling, thread-forming fasteners 54 may be installed throughclearance holes in the second end plate 274 into the inside flange 268.

Alternatively, pilot holes may be provided in the first end plate 272and the inside flange 268 corresponding with the clearance holes, andthe thread-forming fastener 52 may be installed through the clearanceholes and thread-formed into the pilot holes. Alternatively, thefasteners 52, 54 may be thread-formed into the second end plate 274 andthe outside flange 218 by providing clearance holes in the inside flange268 and first end plate 272 accordingly. Optionally, nuts 86 may beprovided on the ends of the thread-forming fasteners 52 orself-drilling, thread-forming fasteners 54. A right-angle impact drivermay be used to drive the fasteners 52, 54 for certain applications whenclearance between the beam flanges is limited. The self-drilling,thread-forming fastener 54 for the application of FIG. 62 may be betweenabout ¼ and ½ inch major diameter as desired for certain loadrequirements. Alternatively, the thread-forming fasteners 52 for theapplication of FIG. 62 may be between about ¼ and 1½ inch, or larger,major diameter for load requirements as desired.

The C-girt 264 may extend between two or more fascia vertical members266 installed into an upper portion of the fascia vertical members 266using self-drilling, thread-forming fasteners 54. Additionally, C girts264 may extend between two or more fascia vertical members 266 securedto the inside flanges 268 of the fascia vertical members 266.

In certain building structures it may be useful to support an overheadcrane or other overhead system. A crane beam member 276 having a bottomflange 278 may be supported by a column member 280 having a top plate282 as shown in FIG. 63A. The bottom flange 278 of the crane beam member276 may be provided with clearance holes larger than the diameter of thethread-forming fastener 52, and the top plate 282 provided with pilotholes, and the thread-forming fastener 52 installed through theclearance holes and thread-formed into the pilot holes in the top plate282. A rail plate 286 may be installed above the crane beam member 176and a crane rail 284 fastened to the cap channel 286 and crane beammember 176 using thread-forming fasteners 52 as shown in FIG. 63B. Railclamps 288 may be positioned to clamp the crane rail 284 and cap channel286 to the crane beam member 176. The rail clamps 288 and cap channel286 may be provided with clearance holes larger than the diameter of thefasteners 52, and pilot holes may be provided in the top of the cranebeam member 176. The thread-forming fasteners 52 may be installedthrough the clearance holes of the rail clamps 288 and cap channel 286and thread-formed into the pilot holes in the top of the crane beammember 176 as shown in FIG. 63B. The thread-forming fasteners 52 for theapplication of FIG. 63A may be between about ¾ and 1½ inch, or larger,major diameter for load requirements as desired. At least a portion ofthe threaded portion 64 may comply with ASTM A325, A490, or otherfastener standard as desired.

A concrete wall panel 380 may be attached to the rafter member 162 usinga bracket 382 connected to an embed plate 384 in the concrete wallpanel. The bracket 382 may be integral with the embed plate 384, such asby welding. Alternatively, the bracket 382 may be fastened to the embedplate 384. The bracket 382 may be installed to the rafter member 162using thread-forming fasteners 52 or self-drilling, thread-formingfastener 54 as shown in FIG. 64. The bracket may be provided withclearance holes 72 and the self-drilling, thread-forming fastener 54installed through the rafter member 164. Alternatively, pilot holes maybe provided through the rafter member 164 and thread-forming fasteners52 installed through the bracket into the pilot holes.

Panels 180 such as shown in FIG. 65 are typically provided in variousthicknesses, sizes, and cross-sectional shapes for use as side-wallsheeting, roof covering, decking, and other uses. Panels 180, anddecking 42 as discussed with respect to FIG. 1, are formed of sheetmetal having steel thicknesses typically between about 10 gage and 16gage. Panels 180 and decking 42 may be installed in lapped connectionsusing self-drilling, thread-forming fastener 56. Alternatively, panels180 and decking 42 may be installed in lapped connections usingself-drilling, thread-forming fastener 54. In one alternative, clearanceholes larger than the major diameter 58 of the fastener 54, 56 may beprovided along one or more edges of the panels 42, 180. To make theoverlapped connection, the clearance holes of one panel are lapped overa second panel, and the self-drilling, thread-forming fastener 54, 56are positioned through the clearance holes and drilled and thread-formedinto the second panel.

Referring now to FIG. 66, a filler panel 182 is provided between an edgeof the deck 42 and the girder 46. In the past, as shown in FIG. 67,filler panels had to be welded in place by weld connections 184. Theweld connections 184 increased the complexity of the installation andrequired a trained welder to be at the job site and delays provided inthe building schedule so welding can be done. The present filler panel182 does not require welding and may be installed using self-drilling,thread-forming fastener 56 or self-drilling, thread-forming fastener 54.The filler panel 182 is provided with a flange 186 having a plurality ofclearance holes larger than the major diameter 58 of the self-drilling,thread-forming fastener 54, 56. The fasteners 54, 56 are positionedthrough the clearance holes and drilled and thread-formed into the deck42. The filler panel 182 may have an alternative shape as shown in FIG.66. By providing flange 186 and fasteners 54, the filler panel 182 maybe installed efficiently by an operator positioned on the deck 42.Alternatively, no clearance holes are provided and the self-drilling,thread-forming fastener 54, 56 installed through both members.

The joist 40 may be provided with L-bracket 154 for mounting a utilityhanger 188. As shown in FIGS. 68 through 70, the utility hanger 188 mayinclude a modified self-drilling, thread-forming fastener 54′ where thehead 63′ comprises a threaded bore 190 adapted to receiving a threadedrod 192. The threaded bore 190 may be cross-drilled, i.e. transverse tothe direction of the threaded portion 64 as shown in FIG. 70.Optionally, the threaded bore may be end-drilled aligned with thedirection of the threaded portion 64 (not shown). The threaded rod 192corresponding to the threaded bore 190 may be turned into the threadedbore after the self-drilling, thread-forming fastener 54′ is installed.Various hangers may be affixed to the threaded rod 192, such as a ring194 as shown in FIG. 68. Alternatively, the threaded rod 192 may beaffixed to a hook (not shown) or other hanger shapes as desired. Toinstall the utility hanger 188, the self-drilling, thread-formingfastener 54 is drilled and thread-formed into the L-bracket 154 or othersupporting member as desired and tightened such that the threaded borein the head 63′ is oriented generally in a vertical direction. Then, thethreaded rod 192 is rotated into threaded engagement in the threadedbore 190.

In the past, utility hangers were installed using bolt-and-nutconnections through pre-drilled holes. Past connections also includedmasonry screws driven into the concrete slab of the floor above. In anyevent, the presently disclosed utility hanger utilizing theself-drilling, thread-forming fastener 54 is able to be efficientlyinstalled in many applications. In one alternative, the utility hanger188 is installed in a bottom chord of a joist or girder (not shown) withself-drilling, thread-forming fastener 54.

In certain joist loading requirements, additional joist bracing may berequired. FIG. 71 shows a chord brace 197 positioned between the topchord 140 and the bottom chord 142 secured by self-drilling,thread-forming fastener 54. The chord brace 197 may be provided with aplurality of clearance holes larger than the major diameter 58 of theself-drilling, thread-forming fastener 54. The self-drilling,thread-forming fastener 54 may be provided through the clearance holesand drilled and thread-formed into the joist. By using the presentself-drilling, thread-forming fastener 54, the chord brace 197 may beinstalled where needed along the joist without pre-drilling holes in thejoist. The chord brace 197 is installed faster and more efficiently withthe fasteners 54 than with prior connections.

Referring now to FIGS. 72 and 73, a plurality of truss members 290 maybe secured to a support member 292 using brackets 294 and self-drilling,thread-forming fasteners 54 and/or self-drilling, thread-formingfasteners 56. The self-drilling, thread-forming fasteners 54, 56 may beinstalled through the bracket 294 into a side of the truss member 290and through the bracket 294 into the support member 292. As shown inFIGS. 72 and 73, various configurations of bracket 294 may be providedas desired. The self-drilling, thread-forming fasteners 54, 56 may havea major diameter between about 0.19 inch (#10 fastener, ASME B1.1Unified Inch Screw Thread Standard) to about 0.25 inch (¼ inch fastener,ASME B1.1 Unified Inch Screw Thread Standard). In the past, prior screwsused to secure trusses failed by stripping out and not providing asecure clamp, and an extra amount of prior screws typically have beenused to accommodate a regular amount of strip out failures. The presentself-drilling, thread-forming fasteners 54, 56 provide a desiredconnection using between 25% and 60% fewer screws than in the past forthe same load requirement. Alternatively, the connection may be securedusing between 35% and 40% fewer screws than when using the prior screws.The reduction in number of fasteners may provide a significant savingsin cost and time for installation.

FIG. 74 shows a blocking member 296 secured between truss member 290providing a closure. A strap member 298 may be provided transverse tothe truss member 290 positioned for securing a portion of the blockingmember 296. The blocking member 296 may be secured between the strap andthe support member 292 using a plurality of self-drilling,thread-forming fasteners 56 and/or self-drilling, thread-formingfasteners 54. The self-drilling, thread-forming fasteners 54, 56 may beinstalled through the blocking member 296 into the strap member 298, andthrough the blocking member 296 into the support member 292 as shown inFIG. 74. The self-drilling, thread-forming fasteners 54, 56 may have amajor diameter between about 0.19 inch (#10 fastener) to about 0.25 inch(¼ inch fastener). As discussed above, the present self-drilling,thread-forming fasteners 54, 56 provide a desired connection usingbetween 25% and 60% fewer screws than in the past for the same loadrequirement. Alternatively, the connection may be secured using between35% and 40% fewer screws than when using the prior screws, providing asignificant savings in cost and time for installation.

A corner jack 300 may be connected to a girder truss 302 using straps304 and a plurality of self-drilling, thread-forming fasteners 54 and/orself-drilling, thread-forming fasteners 56 as shown in FIG. 75. Thestraps 304 may be provided around a vertical web 306, and self-drilling,thread-forming fasteners 54, 56 may be installed through the straps 304into the vertical web 306 and through the straps 304 into the cornerjack 300. The self-drilling, thread-forming fasteners 54, 56 may have amajor diameter between about 0.19 inch (#10 fastener) to about 0.25 inch(¼ inch fastener). The present self-drilling, thread-forming fasteners54, 56 provide a desired connection using between 25% and 60% fewerscrews than in the past for the same load requirement. Alternatively,the connection may be secured using between 35% and 40% fewer screwsthan when using the prior screws, providing a significant savings incost and time for installation.

A plurality of rafters 308 may be secured to a ridge rafter 310 usingL-brackets 312 and a plurality of self-drilling, thread-formingfasteners 54 and/or self-drilling, thread-forming fasteners 56 as shownin FIG. 76. The self-drilling, thread-forming fasteners 54, 56 may beinstalled through the L-bracket 312 into a side of the rafter 308 andthrough the L-bracket 312 into the ridge rafter 310. The self-drilling,thread-forming fasteners 54, 56 may have a major diameter between about0.19 inch (#10 fastener) to about 0.25 inch (¼ inch fastener). Thepresent self-drilling, thread-forming fasteners 54, 56 provide a desiredconnection using between 25% and 60% fewer screws than in the past forthe same load requirement. Alternatively, the connection may be securedusing between 35% and 40% fewer screws than when using the prior screws,providing a significant savings in cost and time for installation.

Roof decking 314 may be secured to a stud wall frame 316 as shown inFIG. 77 using a ledger angle 318 and a plurality of self-drilling,thread-forming fasteners 56 and/or self-drilling, thread-formingfasteners 54. The self-drilling, thread-forming fasteners 54, 56 may beinstalled through the ledger angle 318 into the stud wall frame 316along the desired roof pitch. The roof decking 314 may be secured to theledger angle 318 using self-drilling, thread-forming fasteners 54, 56.The self-drilling, thread-forming fasteners 54, 56 may have a majordiameter between about 0.19 inch (#10 fastener) to about 0.25 inch (¼inch fastener). The present self-drilling, thread-forming fasteners 54,56 provide a desired connection using between 25% and 60% fewer screwsthan in the past for the same load requirement. Alternatively, theconnection may be secured using between 35% and 40% fewer screws thanwhen using the prior screws, providing a significant savings in cost andtime for installation.

FIG. 78 shows a stud wall frame 320 attached to a concrete slab 322 in ashear wall configuration. Diagonal straps 324 and a hold-down attachment326 are secured to the stud wall frame 320. A plurality ofself-drilling, thread-forming fasteners 56 and/or self-drilling,thread-forming fasteners 54 may be used to install the diagonal straps324 to steel studs 328 and lower track 330 of the stud frame wall 320.The hold-down attachment 326 may be attached to the steel stud 328 usingself-drilling, thread-forming fasteners 54, 56. As shown in FIGS. 78 and79, various configurations of hold-down attachment 326 may be providedas desired. The self-drilling, thread-forming fasteners 54, 56 may havea major diameter between about 0.19 inch (#10 fastener) to about 0.25inch (¼ inch fastener). As discussed above, the present self-drilling,thread-forming fasteners 54, 56 provide a desired connection usingbetween 25% and 60% fewer screws than in the past for the same loadrequirement. Alternatively, the connection may be secured using between35% and 40% fewer screws than when using the prior screws, providing asignificant savings in cost and time for installation.

A header beam member 332 may be secured to supporting studs 328 using anL-bracket 334 and a plurality of self-drilling, thread-forming fasteners54 and/or self-drilling, thread-forming fasteners 56, such as shown inFIG. 80. The header beam member 332 may be an I-beam fabricated bywelding top and bottom plates 336 to web member 338. The self-drilling,thread-forming fasteners 54, 56 may be installed through the L-bracket334 into the web member 338 and through the L-bracket 334 into theadjacent stud 328. The self-drilling, thread-forming fasteners 54, 56may be installed through the lower plate 336 into the adjacent stud 328.The self-drilling, thread-forming fasteners 54, 56 may have a majordiameter between about 0.19 inch (#10 fastener) to about 0.25 inch (¼inch fastener). The present self-drilling, thread-forming fasteners 54,56 provide a desired connection using between 25% and 60% fewer screwsthan in the past for the same load requirement. Alternatively, theconnection may be secured using between 35% and 40% fewer screws thanwhen using the prior screws, providing a significant savings in cost andtime for installation.

As shown in FIG. 81, the header beam member may be a box header 340secured to supporting studs 328 using a plate 342 and a plurality ofself-drilling, thread-forming fasteners 54 and/or self-drilling,thread-forming fasteners 56. The box header 340 may include a bottomtrack 344 and a corresponding top track 346 and a plurality of steelstuds 348 assembled in a box beam as shown in FIG. 81. The box header340 may be secured to the supporting studs 328 by installingself-drilling, thread-forming fasteners 54, 56 through the plate 342into the box header 340 and through the plate 342 into the adjacent stud328. The self-drilling, thread-forming fasteners 54, 56 may have a majordiameter between about 0.19 inch (#10 fastener) to about 0.25 inch (¼inch fastener). The present self-drilling, thread-forming fasteners 54,56 provide a desired connection using between 25% and 60% fewer screwsthan in the past for the same load requirement. Alternatively, theconnection may be secured using between 35% and 40% fewer screws thanwhen using the prior screws, providing a significant savings in cost andtime for installation.

FIG. 82 is a partial section view through an outside wall viewing afloor truss 350. The floor truss 350 is supported at one end by lowerwall 352. The floor truss 350 is secured to the lower wall 352 usingL-bracket 358 and a plurality of self-drilling, thread-forming fasteners54 and/or self-drilling, thread-forming fasteners 56. The self-drilling,thread-forming fasteners 54, 56 may be installed through the L-bracket358 into the floor truss 350 and through the L-bracket 358 into a toptrack 356 of the lower wall 352. The floor truss 350 supports an upperwall 354. The upper wall 354 is secured to the floor truss 350 usingself-drilling, thread-forming fasteners 54 through the lower track 330of the upper wall 354 and into the floor truss 350. A lateral member 360may be provided between adjacent floor trusses 350. Self-drilling,thread-forming fasteners 54, 56 may be installed through the lateralmember 360 into the floor truss. The self-drilling, thread-formingfasteners 54, 56 may have a major diameter between about 0.19 inch (#10fastener) to about 0.31 inch ( 5/16 inch fastener). The presentself-drilling, thread-forming fasteners 54, 56 provide a desiredconnection using between 25% and 60% fewer screws than in the past forthe same load requirement. Alternatively, the connection may be securedusing between 35% and 40% fewer screws than when using the prior screws,providing a significant savings in cost and time for installation.

As shown in FIG. 83, a truss member 362 may be connected to a steel stud364 using a plurality of self-drilling, thread-forming fasteners 54and/or self-drilling, thread-forming fasteners 56. The self-drilling,thread-forming fasteners 54, 56 may be installed through a verticalmember 368 of the truss member 362 into the steel stud 364.Additionally, an angle bracket 370 may be installed below the trussmember 362, and optionally an angle bracket 366 may be installed abovethe truss member 362. Self-drilling, thread-forming fasteners 54, 56 maybe installed through the angle brackets 366, 370 into the steel stud364, and through the angle brackets 366, 370 into the truss member 362.The self-drilling, thread-forming fasteners 54, 56 may have a majordiameter between about 0.19 inch (#10 fastener) to about 0.25 inch (¼inch fastener). The present self-drilling, thread-forming fasteners 54,56 provide a desired connection using between 25% and 60% fewer screwsthan in the past for the same load requirement. Alternatively, theconnection may be secured using between 35% and 40% fewer screws thanwhen using the prior screws, providing a significant savings in cost andtime for installation.

Alternatively, the truss member 362 may be secured to a girder truss372. As shown in FIG. 84, the truss member 362 may be secured to thegirder truss 372 using L-brackets 374 and a plurality of self-drilling,thread-forming fasteners 54 and/or self-drilling, thread-formingfasteners 56. The self-drilling, thread-forming fasteners 54, 56 may beinstalled through the L-bracket 374 into the truss member 362 andthrough the L-bracket 374 into the girder truss 372. The self-drilling,thread-forming fasteners 54, 56 may have a major diameter between about0.19 inch (#10 fastener) to about 0.25 inch (¼ inch fastener). Thepresent self-drilling, thread-forming fasteners 54, 56 provide a desiredconnection using between 25% and 60% fewer screws than in the past forthe same load requirement. Alternatively, the connection may be securedusing between 35% and 40% fewer screws than when using the prior screws,providing a significant savings in cost and time for installation.

Disclosed is a method of connecting a plurality of members in a buildingconnection including the steps of providing a first member having afirst mounting surface and a second mounting surface opposite the firstmounting surface and a first member thickness there between, providingat least one fastener having a thread-forming portion and a threadedportion, positioning a second member having a first aperture adjacentthe first mounting surface, installing the fastener through the firstaperture and forming threads in a fastener opening through the firstmember thickness connecting the second member to the first member withthe thread-forming portion extending through the second mountingsurface, positioning a third member having a second aperture larger thanthe major diameter of the threaded portion adjacent the second mountingsurface such that the second aperture is positioned over the threadedportion, and installing a nut over the threaded portion to connect thethird member to the first member.

While the invention has been described with reference to certainembodiments it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the invention without departing from its scope.Therefore, it is intended that the invention not be limited to theparticular embodiments falling within the scope of the appended claims.

What is claimed is:
 1. A building structure comprising: a first steelbuilding member and a second steel building member connected by aplurality of fasteners, each fastener being steel comprising a headcapable of clamping the first steel building member to the second steelbuilding member with the fastener installed, a threaded portion adjacentthe head, a thread-forming portion of at least HRC 50 hardness adjacentthe threaded portion adapted to form threads into at least the secondsteel building member, and a fluted lead portion of at least HRC 50hardness adjacent the thread-forming portion with a nominal diameter ina range from 60% to 95% of major diameter of the threaded portionadapted to form a fastener opening, the thread-forming portion having aseries of lobes with recesses between said lobes having a ratio of striptorque to thread-forming torque of at least 3.0 and a ratio of striptorque to drive torque greater than 6.0 over a range of combinedthickness of first and second steel building members from about 0.036inch to 0.084 inch, the lobes positioned about the rotational axis. 2.The building structure of claim 1 where each lobe having a leadingportion and a tailing portion, the leading portion and first adjacentrecess at a first angle in a range from 50° to 100° from a plane tangentto the lobe adjacent the leading portion, and the tailing portion andsecond adjacent recess at a second angle in a range from 25° to 50° froma plane tangent to the lobe adjacent the tailing portion, where thefirst angle is greater than the second angle.
 3. The building structureof claim 1 where the ratio of strip torque to thread-forming torque isat least 3.0 and a ratio of strip torque to drive torque greater than8.0 over a range of combined thickness of first and second steelbuilding members from about 0.036 inch to 0.084 inch.
 4. The buildingstructure of claim 1 where the ratio of strip torque to thread-formingtorque is at least 3.0 and a ratio of strip torque to drive torquegreater than 6.0 over a range of combined thickness of first and secondsteel building members from about 0.036 inch to 0.108 inch.
 5. Thebuilding structure of claim 1, where the threaded portion adjacent thehead has a through hardness in a range from HRB 70 and HRC
 40. 6. Thebuilding structure claimed in claim 5, where the fasteners have up tofive threads between the threaded portion and the thread-forming portionhardened to at least HRC 50 hardness.
 7. The building structure claimedin claim 1, where the fasteners are nutable.
 8. The building structureclaimed in claim 1, where the combined thickness of the first steelbuilding member and the second steel building member at the fastener isno more than 0.125 inch in thickness.
 9. The building structure claimedin claim 1, where the fluted lead portion has a nominal diameter in arange from 62% to 85% of major diameter.
 10. The building structureclaimed in claim 1, where the thread-forming portion has a shapeselected from a group consisting of quadlobular and pentalobular. 11.The building structure claimed in claim 1, where the lead portion of thefluted lead portion has a milled point.
 12. The building structureclaimed in claim 1, where the fluted lead portion has at least HRC 50induction hardness.
 13. The building structure claimed in claim 1, wherethe threaded portion has less than 60° thread angle and back-taperedthreads.
 14. The building structure claimed in claim 1, where thethreaded portion has from 45 to 50° thread angle and back-taperedthreads.
 15. The building structure claimed in claim 1, where thethread-forming portion is from 3 to 7 thread pitch in length.
 16. Thebuilding structure claimed in claim 1, the threaded portion comprising amajor diameter extending to within 1.5 of the thread pitch of the head.17. The building structure claimed in claim 16, where the head of thefasteners are undercut and adapted to deform the first steel buildingmember on tightening of the fasteners.
 18. The building structureclaimed in claim 1, where a sealing member is positioned between thehead and the threaded portion.
 19. The building structure claimed inclaim 1, where serrations are provided in the underside of the head. 20.A building structure comprising: a first steel building member and asecond steel building member connected by a plurality of fasteners, eachfastener being steel comprising a head capable of clamping the firststeel building member to the second steel building member with thefastener installed, a threaded portion adjacent the head, athread-forming portion of at least HRC 50 hardness adjacent the threadedportion adapted to form threads into at least the second steel buildingmember, and a fluted lead portion of at least HRC 50 hardness adjacentthe thread-forming portion with a nominal diameter in a range from 60%to 95% of major diameter of the threaded portion adapted to form afastener opening, the thread-forming portion having a series of lobeswith recesses between said lobes having a ratio of strip torque tothread-forming torque of at least 4.0 and a ratio of strip torque todrive torque greater than 8.0 over a range of combined thickness offirst and second steel building members from about 0.054 inch to 0.084inch, the lobes positioned about the rotational axis.
 21. The buildingstructure of claim 20 where the ratio of strip torque to thread-formingtorque is at least 4.0 and a ratio of strip torque to drive torquegreater than 10.0 over a range of combined thickness of first and secondsteel building members from about 0.054 inch to 0.084 inch.
 22. Thebuilding structure of claim 20 where the ratio of strip torque tothread-forming torque is at least 3.5 and a ratio of strip torque todrive torque greater than 6.0 over a range of combined thickness offirst and second steel building members from about 0.036 inch to 0.084inch.
 23. The building structure of claim 20 where the ratio of striptorque to thread-forming torque is at least 3.5 and a ratio of striptorque to drive torque greater than 8.0 over a range of combinedthickness of first and second steel building members from about 0.036inch to 0.084 inch.
 24. The building structure of claim 20 where theratio of strip torque to thread-forming torque is at least 3.0 and aratio of strip torque to drive torque greater than 4.0 over a range ofcombined thickness of first and second steel building members from about0.036 inch to 0.108 inch.
 25. The building structure of claim 20, wherethe threaded portion adjacent the head has a through hardness in a rangefrom HRB 70 to HRC
 40. 26. The building structure claimed in claim 25,where the fasteners have up to five threads between the threaded portionand the thread-forming portion hardened to at least HRC 50 hardness. 27.The building structure claimed in claim 20, where the fasteners arenutable.
 28. The building structure claimed in claim 20, where thecombined thickness of the first steel building member and the secondsteel building member at the fastener is no more than 0.125 inch inthickness.
 29. The building structure claimed in claim 20, where thefluted lead portion has a nominal diameter in a range from 62% to 85% ofmajor diameter.
 30. The building structure claimed in claim 20, wherethe thread-forming portion has a shape selected from a group consistingof quadlobular and pentalobular.
 31. The building structure claimed inclaim 20, where the lead portion of the fluted lead portion has a milledpoint.
 32. The building structure claimed in claim 20, where the flutedlead portion has at least HRC 50 induction hardness.
 33. The buildingstructure claimed in claim 20, where the threaded portion has less than60° thread angle and back-tapered threads.
 34. The building structureclaimed in claim 20, where the threaded portion has from 45 to 50°thread angle and back-tapered threads.
 35. The building structureclaimed in claim 20, where the thread-forming portion is from 3 to 7thread pitch in length.
 36. The building structure claimed in claim 20,the threaded portion comprising a major diameter extending to within 1.5of the thread pitch of the head.
 37. The building structure claimed inclaim 36, where the head of the fasteners are undercut and adapted todeform the first steel building member on tightening of the fasteners.38. The building structure claimed in claim 20, where a sealing memberis positioned between the head and the threaded portion.
 39. Thebuilding structure claimed in claim 20, where serrations are provided inthe underside of the head.
 40. A building structure comprising: a firststeel building member and a second steel building member connected by aplurality of fasteners, each fastener being steel comprising a headcapable of clamping the first steel building member to the second steelbuilding member with the fastener installed, a threaded portion adjacentthe head having a through hardness in a range from HRB 70 to HRC 40, athread-forming portion of at least HRC 50 hardness adjacent the threadedportion adapted to form threads in at least the second steel buildingmember, and a fluted lead portion of at least HRC 50 hardness adjacentthe thread-forming portion with a nominal diameter in a range from 75%to 95% of major diameter of the threaded portion adapted to form afastener opening, the thread-forming portion having a series of lobeswith recesses between said lobes having a ratio of failure torque tothread-forming torque of at least 3.0 and a ratio of failure torque todrive torque greater than 6.0 over a range of combined thickness offirst and second steel building members from about 0.10 inch to 0.32inch, the lobes positioned about the rotational axis.
 41. The buildingstructure claimed in claim 40, where the fasteners are capable ofproviding a ratio of failure torque to thread-forming torque of at least3.75.
 42. The building structure claimed in claim 40, where thefasteners have a drive torque no more than 50% of a thread-formingtorque.
 43. The building structure claimed in claim 40, where thefasteners have up to five threads between the threaded portion and thethread-forming portion hardened to at least HRC 50 hardness.
 44. Thebuilding structure claimed in claim 40, where the fasteners are nutable.45. The building structure claimed in claim 40, where the lead portionof the fluted lead portion has a milled point.
 46. The buildingstructure claimed in claim 40, where the thread-forming portion has ashape selected from a group consisting of quadiobular, pentalobular, andhexalobular.
 47. The building structure claimed in claim 40, where thefluted lead portion has at least HRC 50 induction hardness.
 48. Thebuilding structure claimed in claim 40, where the threaded portion hasless than 60° thread angle and back-tapered threads.
 49. The buildingstructure claimed in claim 40, where the threaded portion has from 45 to50° thread angle and back-tapered threads.
 50. The building structureclaimed in claim 40, where the thread-forming portion is from 3 to 7thread pitches in length.
 51. A building structure comprising: a firststeel building member and a second steel building member connected by aplurality of fasteners, each fastener being steel comprising a headcapable of clamping the first steel building member to the second steelbuilding member with the fastener installed, a threaded portion adjacentthe head having a through hardness in a range from HRB 70 to HRC 40, athread-forming portion of at least HRC 50 hardness adjacent the threadedportion adapted to form threads in at least the second steel buildingmember, and a fluted lead portion of at least HRC 50 hardness adjacentthe thread-forming portion with a nominal diameter in a range from 80 to92% of major diameter of the threaded portion adapted to form a fasteneropening, the thread-forming portion having a series of lobes withrecesses between said lobes having a ratio of failure torque tothread-forming torque of at least 3.0 and a ratio of failure torque todrive torque greater than 10 when the second steel building memberhaving a thickness of about 0.25 inch, the lobes positioned about therotational axis.
 52. The building structure claimed in claim 51, wherethe fasteners are capable of providing a ratio of failure torque tothread-forming torque of at least 3.0 and a ratio of failure torque todrive torque greater than 10 over a range of second steel buildingmember thickness from 0.25 inch to 0.38 inch.
 53. The building structureclaimed in claim 51, where the fasteners are nutable.
 54. The buildingstructure claimed in claim 51, where the fasteners have a drive torqueno more than 50% of a thread-forming torque.
 55. The building structureclaimed in claim 51, where the fasteners have up to five threads betweenthe threaded portion and the thread-forming portion hardened to at leastHRC 50 hardness.
 56. The building structure claimed in claim 51, wherethe lead portion of the fluted lead portion has a milled point.
 57. Thebuilding structure claimed in claim 51, where the thread-forming portionhas a shape selected from a group consisting of quadlobular,pentalobular, and hexalobular.
 58. The building structure claimed inclaim 51, where the fluted lead portion has at least HRC 50 inductionhardness.
 59. The building structure claimed in claim 51, where thethreaded portion has less than 60° thread angle and back-taperedthreads.
 60. The building structure claimed in claim 51, where thethreaded portion has from 45 to 50° thread angle and back-taperedthreads.
 61. The building structure claimed in claim 51, where at leasta portion of the threaded portion of the fasteners meet a specificationselected from a group consisting of ASTM A307, ASTM A325, ASTM A354, andASTM A490 specifications.
 62. The building structure claimed in claim51, where at least a portion of the threaded portion of the fastenersmeet a specification selected from a group consisting of SAE J429 Grade2, SAE J429 Grade 5, and SAE J429 Grade
 8. 63. The building structureclaimed in claim 51, where the thread-forming portion is from 3 to 7thread pitches in length.